Fig. 5. Female.

PARASITES ON CURRANT SPAN WORM.

The currant span worm, Eufitchia ribearia, Fitch, appeared in central Michigan in alarming numbers the past season (1890) for the first time. (See report State Board of Agriculture, 1890, p. 110.) Though apparently a new comer, it was not without enemies from the very first. Upon close examination we found almost as many cocoons of parasites as we found span worms. These were cocoons of the bright yellow Braconid Meteorus Communis, Cresson. (Fig. 5.) The larva when full grown comes forth from its victim and suspends its minute oval brownish cocoon to the twigs by means of a fine silken thread. In a few days the fly comes forth to renew the good work of destroying the span worm.

The fly is about the size of M. bakeri. It is uniform honey yellow in color, though in some specimens the antennæ and portions of the feet are dusky. It is described in Canadian Entomologist, Vol. IV, p. 82. From the exceeding numbers of this insect it must have done royal service in depleting the numbers of the span worms. It preys upon other insects besides the span worm.

THE BEAUTIFUL MESOCHORUS.

From a large number of cocoons which were gathered from twigs where Eufitchia ribearia were feeding, we reared two other parasites, belonging to the family Ichneumonidae, both of which I think are new species. It is to be hoped that these are parasites on the span worms, but as the cocoons were so very similar to those of the Braconid, last referred to, I fear that these may be parasites on that insect.

MESOCHORUS PULCHELLUS, N. SP.

This handsome parasite (Fig. 6) belongs to the sub-family Ophionine, as the ovipositor is short, abdomen slightly compressed posteriorly and petiolate and the areolet rhomboidal. The rhomboidal areolet and the exserted ovipositor show that it belongs to the genus Mesochorus.

The color is honey yellow beautifully marked with black. The antennæ are long, and dusky. The tips of the mandibles, compound eyes, and a triangular spot containing the ocelli are black. Mesochorus pulchellus, Female. Abdomen side view. The center of the mesothorax anteriorly is black and a dusky central line extends back from this nearly or quite to the scutellum. The lateral margins of the mesonotum are black.

Fig. 6.

The scutellum is margined with black, and a V shaped black spot marks the metathorax. The tegulæ are light yellow. The wings are hyaline, iridescent, stigma and nervures black. The bases of the nervures are light yellow. The legs are light yellow. The posterior tibiæ have each a black spot at each end. The abdomen is spindle shaped, rather slender at the

base. The first segment is wholly black, triangular, narrowest at the base. The second segment has a V shaped black spot at the base, while the anterior angles and a broad semi circle at its posterior margin are yellow. The third segment has a broad black posterior crescent, which reaches anteriorly to the angles. The three posterior segments are yellowish brown, and the fifth and sixth are dusky on the posterior border. The ovipositor is black. Entire under parts light yellow. Length three thirty-seconds of an inch.

This species is quite like Mesochorus Americanus, Cress. (Canadian Entomologist Vol. IV, p. 23). It differs in its yellow mesothorax, dusky antennæ, black nervures, and stigma, black spot at base of posterior tibiæ and in the black markings on the dorsal surface of the abdomen.

THE BLACK HEADED ISCHNOCERUS.

The other species which we reared from the cocoons formed by parasites from Eufitchia ribearia was also an Ichneumon fly. In this species the ovipositor is exserted, quite long, areolet is incomplete, the parapsidal grooves of the mesothorax distinct, and the gastrocoeli wanting. Thus this species belongs to the sub-family Cryptinæ.

The areolet is absent. The first abdominal segment expanded at the apex, and the spiracle is behind the middle. There are two transverse carinæ on the metathorax, and the abdomen is not broader than the thorax Thus our species belongs to the genus Ischnocerus. Mr. Cresson gives this as a genus with no described American species.

ISCHNOCERUS NIGRICAPITATUS, N. SP. FEMALE.

The

The color is black marked with brown. head is smooth, shining black with a very fine pubescence. The antennæ (Fig. 7) are long, recurved, and slightly enlarged toward the ends. Each antenna has twenty-seven joints. The scope and the two or three following joints are honey yellow, but each succeeding joint is more dusky. The entire club is dusky. The labrum is yellowish, mandibles brown, and the palpi whitish. The entire thorax, like the head, is Fig. 7. Female. Abdomen side view. intense black. The parapsidal grooves are distinct. The mesothorax has very fine transverse striæ, and is finely pubescent. The metathorax is sub-quadrate, faintly rugulose and pubescent. The tegulæ are whitish; the wings hyaline, iridescent and slightly pubescent. The venures and stigma are dusky, except at base where they are whitish; legs yellowish brown except knees and tips of last tarsi which are dusky. The abdomen is petiolate, broad and hairy. The first segment is black, longitudinally striate and broadens abruptly beyond the middle. The second, third and fourth segments are brown. The lateral margins of the second and the broad lateral and narrow posterior margins of the fourth are dusky. The fifth and sixth segments are dusky, with a slight posterior brownish border. The ovipositor is brown, the guides black. Length three thirty-seconds of an inch.

THE PEACH LOUSE-APHIDIUS.

The past season (1890) the common peach louse, Myzus persica, was a serious pest in many parts of Michigan. This well-known aphis is only one-twelfth of an inch long. The body is greenish black, marked with black. The antennæ are black and the abdomen and legs yellowish brown, the latter marked with black. These lice work on the under side of the leaves which they cause to roll up or curl. The leaves become pitted beneath and bunched above, and soon fall from the trees. The past season one of my pupils, Mr. C. F. Baker, reared a large number of Braconid parasites from these lice. The parasites served greatly to reduce the number of lice, and it is to be hoped that they will prove as efficient as did the closely related Aphidius granariaphis in clearing the grain fields of the grain louse in the summer of 1889. This proves to be a new species so far as I can ascertain.

In this species the abdominal segments are quite freely movable, so that the abdomen bends readily under the thorax. The venation of the posterior wings is very simple, indicating the sub-family Aphidiinæ. The first discoidal cell is incomplete. The abdomen is lanceolate, the antennæ fifteen jointed, and so we have the genus Aphidius.

APHIDIUS PERSIAPHIS, N. SP., MALE.

The first

This species (Fig. 8) is black with scattering lightish hairs. The head is smooth, shining black and very slightly hairy. The compound eyes and ocelli are prominent and intense black. The antennæ are black with fifteen joints. two are rounded, the remaining ones elongated. The palpi are whitish yellow. The entire thorax is shining black. The wings are transparent and iridescent. The venures and stigma are dusky. The front legs are yellow, the middle ones yellow or dusky, the posterior ones usually dusky. All the legs have a yellowish tinge and may vary between yellow and dusky. The first joint or petiole of the abdomen is yellow, the remaining segments black or dusky. Underneath the thorax is black, the abdomen yellowish, becoming dusky or black toward the tip. The length is one-sixteenth of an inch. Described from several specimens.

PARASITES ON HETEROCAMPA SUBALBICANS.

Fig. 8. Male.

The common linden caterpillar, Heterocampa subalbicans, Grote, was exceptionally common in central Michigan in 1890. This gray moth, variously marked with black and white, lays her eggs on basswood and elm. The larvæ which are often very common in autumn, are wondrously beautiful and varied. The combination of delicate green and brilliant red is exquisite.

During the past autumn, we found about the larva on the leaves, symmetrically arranged, often in a circle, groups of pupa of some parasite. These pupa were remarkable for their abundance, their style of arrangement, and for a mass of fecal matter adjacent to each one.

Thus

they formed curious objects, and though so minute, attracted the attention of several of my students.

From these pupa, which in some cases we derive from the larvae, we reared two very interesting chalcid parasites, a few black ones, of the genus Cratotechus, which I think were probably the real parasites of the caterpillar, and many more beautiful, shining metallic green of the genus Derostenus. In several cases we reared only species of these latter, though in many cases we got both species and both sexes from the same group of

pupæ.

THE BEAUTIFUL DEROSTENUS.

The nine jointed antennæ, four jointed tarsi, broken sub-marginal vein, narrow costal cellure, short post-marginal and stigmal veins, single spur to the posterior tibiæ, two bristles to the sub-marginal vein, small metapleura, and double bristles on the mesoscutellum determine the subfamily Ente doninæ, as given by Howard in his synopsis (Entomologica Americana, Vol. 1, p. 198).

The funicle of the male antennæ is not toothed, the mesoscutellum has no median furrow, wings with no appearance of cells, even from the arrangement of hairs; post marginal vein unbroken, abdomen short, and antennæ nine jointed; thus we know that this resplendent Chalcid belongs to the genus Derostenus (see Howard's Synopsis Entomologica

Americana, Vol. 2, p. 100).

Fig. 9.

DEROSTENUS SPLENDENS, N. SP. (FIG. 9).

Shining metallic green. The head is broad, and like nearly the whole body finely imbricated, which produces the beautiful iridescence, sparsely covered with short, white hairs. Ocelli and compound eyes purplish black and prominent, the latter bearing short, stiff hairs. The antennæ are nine jointed. The first four joints. are small, smooth, and the third and fourth or ring joints very short. The other joints are moniliform, hairy and subequal, the last one elongate, tapering to the end. A shallow declivity on the front receives the antennæ. The thorax is broad and quadrangular. Besides the short hairs there are bristles, six on the prothorax, two pairs on the mesoscutum, and smaller ones on the metathorax. The prothorax is narrow and crescent-shaped. The parapsidal grooves and a central longitudinal depression mark the mesoscutum. The scutellum is rounded and prominent. The post-scutellum is narrow. The metathorax has two lateral sub-quadrangular elevations, and a narrow posterior extremity where it joins the abdomen. The wings are beautifully iridescent and slightly hairy. The submarginal vein is broken close to the base and bears two bristles. The post-marginal and stigmal veins are very short. The legs are green, except the tarsi, the first three joints of which are white and the last black in all the feet.

The anterior legs have the femora slightly curved, fusiform, a very ttle longer than the tibiæ. The tibia bear each a short spur. In the middle legs the femur is slender. The posterior legs have very large sub

globular coxæ and fusiform femora. All the legs are slightly hairy. The abdomen is short and heavy. The first segment is long, the other six short and subequal. Length, one and one-fourth m. m. or .05 of an inch. Described from many specimens.

Since writing the above we have reared, April 14, 1890, several more of this species from the same peculiar groups of pupa, which came from the oak caterpillar, Edema albifrons, and which passed the winter as pupæ.

The other species, bred from the groups of pupa, though not so numerous, were also quite common. We bred several specimens of both

sexes.

THE SHORT-HEADED CRATOTECHUS.

This species belongs to the same section as does the Derostenus. The antennæ in the female are obviously six-jointed. If there be other joints they are very obscure. The tarsi are four-jointed, the prothorax prominent, mesoscutellum with four bristles, sub-marginal vein not broken, post-marginal distinct, petiole short and obscure (it is usually marked in this sub-family) parapsides absent, the posterior coxæ not large, postmarginal and stigmal veins quite long. Thus we have the sub-family Eulophinæ. The scutellum is without dorsal lines, antennæ are inserted low down, parapsidal sutures wanting, posterior tibiæ with two spurs, marginal veins less than three times as long as the stigmal, antennæ of the male three-branched. Thus we have the genus Cratotechus.

CRATOTECHUS BREVICAPITATUS, N. SP.-FEMALE.

Color black, with a bronze or greenish reflection, coarsely pitted, resembling the outside of a thimble, slightly hairy. The hairs are short and whitish. The head is wide transversely (Fig. 10), but very narrow from before back, the vertex being a mere ridge. The front is excavated for the antennæ. Two ocelli are situated on the edge of the apex, one in front and below. The compound eyes are oval, elongated from above downward, broadest below. They are mottled with light and brown. The antennæ are inserted low down on the front. The scape reaches nearly to the tip of the vertex, it and the last joint of the antennæ are white, the other joints are dark. The second joint is small, third, fourth and fifth subequal, sixth elongated and tapering.

Fig. 10. Female. a, Antenna of Male.

The prothorax is broad, and narrow from before back; the anterior and posterior margins parallel. The mesothorax is prominent, parapsidal grooves absent, lateral lobes distinct, the scutellum prominent; lateral white bristles margin the metathorax, and four black ones mark the mesoscutellum. The post scutellum and metathorax are wide and narrow from before back, the latter narrowed posteriorly to join the abdomen. The wings are transparent, iridescent, slightly clouded in the center. The basal half of each wing is nearly bald, the outer hairy; the submarginal and marginal veins are nearly equal, the post marginal and stigmal rather long and subequal. The posterior wings have an angle in the submarginal vein which is about equal to the marginal. Short bristles project from the latter. A rim of short hairs fringe this wing as they do the margin about the internal angle of the anterior wing. The secondary wings are nearly