C.T. Brues.
The Braconoid Genus Trachypetus Guérin.
Psyche 27:59-61, 1920.

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19201 Howe-Odonata of Chaihum, Masmchwetts 59 THE BRACONID GENUS TRACHYPETUS GURRIN.
BY CHARLES T. BRUES~
Bussey Institution, Harvard University.
In 1839 Gu6rin1 published an account of a very strange Austra- lian Braconid for which he erected the genus Trachypetus. He
placed Trachypetus in proximity to Helcony Sigalphus and Chelonus and recent authors (e. g. Ashmead and Szhpligeti) have tabulated it as a member of the Chelonin~, next to sphmopyx. Apparently this insect remained unknown in nature ta hymenop- terists since Gu6rinys time, until 1911 when Schulz2 examined two specimens in the Saussure collection, obtained in New South Wales. Schulz (loc. cit.) makes Trachypetus the type of a new subfamily Trachypetine which he places provisionally in the " Cryptogastrini." Among thesey he would distinguish the Trachy- petince by the petiolate abdomen in which the first segment is articulated to and not fused with the post-abdomen as is the case in the other Cryptogastrini except Sphteropyx? Last summer, I received from Dr. R. J. Tillyard, two specimens of a magnificent Braconid collected at Woy WoyY Queensland, which Dr. Tillyard was unable to place satisfactorily in any family. These prove to be Gu6rin9s Trachgpetus clavatus which is very carefully described at considerable length in the first publica- tion cited abovey and in still greater detail by Schulz. Trachypetus is undoubtedly a Braconid, but it is much more difficult to locate it in any of the recognized subfamilies. Super- ficially it is somewhat similar to Sphmopyx in the form of the abdomen whichy however, lacks the deeply concave venter charac- teristic of the Cheloninie.
The wings, aside from the radial cell,
and the neuration of the hind pair, are somewhat like those of Sphmopyx as are hlso the form of the propodeum, multiarticulate antenn~ and the legs; herey howevery the similarities cease. There 1 Voyage de la CoquiUe, Z061,. vol. 2, pt. 2, p. 201; aflas, PI. 8, fig. 7. 2 Zd. Ann., vol. 4, p. 85.
@$phmopyx includes one well known and widespread European specie^, S. iwor& Fabr. and ~everal North American swcies described by Provaneher and Creason. Whether all thm may be conaidered as mugeneric, I do not know, but crew on'^ species, 8. bimlor is quite similar to 8. irrwafor and could s~arcely be separated although much smaller and of somewhat Werent habitus,
I do not know Tetrmphmopyx Ashmead which i~ bsed on Rhoga~ pihw Cmsmn, but Mr. Rohwer has kindly examined Ashmead's type and writes me that it i~ a Rhogadiie.



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is no <ilm mouth+ping, which at once removes Trachypetu from the sevd mlifamilies of the group Cyclosbmi, with none, of which it has otherwise any characters in common, except per- haps the fact that the abdomen resembles slightly that of some Fig. I,
TrachgpeLw damha Guhim; hdy from above and h d from tbe front; wing of Sphmopyx above, of lkachypd~ blow. S ~ ~ ~ . It could not possibly be placed in this group and muat fall in the PoIymorphi, with several groups of which it appears t~ be died, although not wily referable to any one of them



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19201 Brues-The Braconid Genus Trachypetus Gdrin 6 1 As it has been placed in the Cheloninie, I shall first compare it with the members of this subfamily. Of these only Spheropyx has the abdomen petiolate with an actually flexible articulation between the petiole and the post-abdomen. In that genus the carapace is divided by a deep, crenulate suturiform articulation, so that so far as the abdomen is concerned Spheropyx is more like a Braconine than Chelonine if we take Chelonus, Ascogaster, or even Phanerotoma as typical of this subfamily. In neuration,
except for the truncate radial celly Trachypetus is rather similar to Spheropyxy neither of which closely resembles any Chelonine. Indeed the neuration of certain Sigalphine is more like that of these two genera except for the presence of only two cubital cells and a less complete venation in the hind wing. Beyond the petiole the abdomen of Trachypetus is practically unsegmented although there is a trace of the suturiform articulation, a condition met with occasionally in groups other than the Chelonine and Sigal- phine.
As to its relation to other groups of the Polymorphi, Trachypetus appears to be very generalized. The abdomen is clearly petiolate as in the Meteorine and Euphorin~ and Helorimorphin~ with which it clearly has no close affiinity. There are three cubital cells and a large, complete radial cell as in the Macrocentrini and Helconinz, to which latter group it shows, I think, the closest affinities. Several genera of Helconinz with the abdomen clavate have been described, such as Brull6ia Szkp. from New Guinea, and Euscelinus Westw. from Borneo, while Hymenochaonia D. T. (Chaonia Cress.) from Cuba may possibly belong here. None of these, however, have the segments of the post-abdomen so com- pletely fused and all may be quite different from Trachypetus, as I unfortunately do not know them in nature. Spheropyx lacks \
the thick Helconine head, which is present in Trachypetus. Aside from the closed marginal cell, the neuration is quite like that of Cardiochiles Nees. as is also the structure of the head, thorax and legs.
Even outside the family Braconidze, the fusion of the abdomind tergites into a carapace or shield-like piece occurs and this character alone is in no way distinctive of the Cheloninz. Thus in the Aly- siide, Symphya has a typical carapace and even in Vanhornia, the type of quite a different family with exodont mandibles the upper surface of the abdomen forms a carapace.



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6% Psyche [April-June
From the foregoing it would appear that Trachypetus is a very generalized Braconid, perhaps best placed in the subfamily Hel- conin* as at present understood unless it be separated as Schulz has done as a monotypical subfamily known only by one species in one sex, a position of very doubtful stability. As I believe that the present unsatisfactory classification of the Braconid* as a whole can be improved only by a careful examination of the quite considerable number of apparently aberrant forms, I have taken this occasion to discuss and figure Trachypetus. AN INFESTATION OF THE WHITE-PINE APHID.
BY H. B. PEIRSON,
Bussey Institution, Harvard University.
While working at the Harvard Forest, Petersham, Mass., my attention was called to a somewhat isolated clump of white-pine trees, forty to fifty years old, which were dying. The trees averaged about fourteen inches D. B. H. and were approximately twelve in number. On two sides of the clump of mature trees were young white-pine plantations. A careful examination showed that the trees were being killed due to an extremely heavy infestation of black aphids which upon identification proved to be Lachnus strobi Fitch., the White-pine Aphid. Many of the larger limbs were barren of foliage, whereas on others the foliage was brown, the individual needles each showing many puncture marks where the aphids had been feeding.
The trees were first examined October 10, 1919, at which time the aphids were laying their eggs on the needles. These are laid end to end generally in lines of five or six, although as many as twenty-seven were found on a single needle, and it was not at all uncommon to find as many as ten or fifteen attached end to end. The eggs were invariably laid on the green needles, and the aphids apparently anticipating the death of the older trees were laying the majority of the eggs on the younger trees in one of the adjacent plantations. Practically all of the needles on the more heavily infested trees had batches of eggs on them. Large numbers of the aphids were still feeding. These had congregated on the needles and small twigs. The survival of the



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