NATURAL ENEMIES OF THE LOCUST. 
2GD 
the legs aro all shorter; the prothoracic spiracles less conspicuous; the hairs ou ab- 
dominal joints shorter; the transverse dorsal teeth smaller and in single row; the 
hasal abdominal joint •without spines, but with long stout hairs and the dorsal tuber- 
cles of abdominal joint 9 replaced by a single spine. 
Imago (PI. XVI, Figs. 6, 7).— The generic characters as indicated in our figures, and 
especially the larger head and eyes, more slender form, and short proboscis readily 
distinguish this from the Systcsclius. The sexes are also readily separated by the more 
pronouuced transverse rows of white or tawny hairs on the hind borders of the abdom- 
inal joints in the female. The genus in some degree connects the Anthradni with 
the more typical Bombyliini. In certain lights the tegument reveals a greenish tinge, 
and the pubescence of the thorax appears generally of a tawny color. The male some- 
times has a white tomentum on the front, and in some specimens there is a stump of 
a vein extending into the discal cell. We quote the original description : 
Triodites mus, $ 9 . — Uniformly clothed with whitish-gray pile ; face with white 
pile ; wing hyaline. Length 8-9 mm . 
Male. — Frontal triangle black, with short, erect, black pile ; face with a dense 
covering of short snow-white pile ; antennae black ; occiput black, with appressed 
white hairs along the orbits; thorax grayish-black, with a dense covering of delicate, 
downy, whitish-gray pile, which in an oblique light looks altogether white ; the few 
bristles on the antescutellar callosities and on the scutellum are whitish, almost 
colorless ; abdomen black, with the same covering of grayish-white pile, which is 
longer here on the sides. Halteres whitish ; knob brownish. Legs black, densely 
clothed with white scales ; spines on femora and tibiae whitish-yellow. Wings, in- 
cluding the costal cell, of a pure hyaline; veins, except at the root, black ; costal and 
first longitudinal brown. 
Female. — Like the male, but the front is slightly brownish-pruinose, and has, besides 
the erect, black pile, some short, recumbent, yellowish hairs. The hind margin of 
the abdominal segments are beset with some short, appressed, whitish hairs, forming 
cross-bands. 
Bab. — I have a single male, which I took near the Salt Lake, Utah, August 1. One 
of the females is from Sonoma County, California, July 6 ; the other from the Shasta 
district (H. Edwards, July, 1875). 
As the larvae from the Mississippi Valley, so far as ascertained, belong 
to Systcechus, and as the Triodites is not yet known to occur east of Utah, 
we conclude that the former genus is the one most affecting the locusts 
in the Mississippi Valley. 337 
337 Since the above was written aud in type we have met with an article, previously 
overlooked, "On the Economy, &c, of Bombylius," by T. Algernon Chapman, M. D., 
in the Entomologist's Monthly Magazine for February, 1878, vol. 14, p. 196. Mr. Chap- 
man gives abundant proof of the parasitism of the European B. major on Andrenalabialis. 
He records some observations on the oviposition of Bombylius, the small white egg being 
thrown with a short jerk against the earth near where the food of its future larva presum- 
ably occurred. This would also imply that, as in the case of the Blister-beetles, the 
newly-hatched larva must seek its food, and strengthens our suspicion that it will be 
found to be much more active than the mature larva. Mr. Chapman very fully de- 
scribes the mature larva and the pupa, and his descriptions show that in all essential 
points the larva of Bombylius accords with those of Triodites and Systoechus. We quote 
his description of the head : "The head is set into this segment [the 1st thoracic] and 
is retractile. It is very small ; its center is occupied by a prominent wedge-shaped 
portion, the point of the wedge being downwards and immediately in front of the 
mouth. Immediately behind this are two black, very sharp, setiform jaws(?); on 
each side is a papillary eminence (antenna?) of three joints set in a circle of softer 
tegument, and immediately below project downward on each side two large palpi 
(labrum?), looking like jaws, but having a vertical, not a lateral, mobility. On the 
anterior surface of each of these there is a palpusof some length, apparently unjointed, 
set in a circle." It will thus be seen that he homologizes the parts much as we have 
done, except that he refers the two lower palpigerous pieces, with a question, to the 
24 L 
