> xv’) 
First Report (1877) emanating from the same source, we invite special 
attention—Professor Riley supplies “ Further facts about the natural 
enemies of the Locusts ” (chap. xiii., pp. 259—271, pl. xvi.), and narrates the 
‘interesting and hitherto unrecorded life-history” of two Dipterous insects 
belonging to the family Bombyliide (Triodites mus, O. 8., and Systachus 
oreas, O. S.), whose larvee prey upon locust eggs to a considerable extent 
(p. 263), but the perfect insect was not bred until June of last year (1880). 
These larve closely coincide in structural details with those from the Troad, 
and have been found in Minnesota, Iowa, Missouri, Kansas, Nebraska, 
Utah, Washington Territory, and California. The Systwchus is observed 
abundantly darting and buzzing about over the ground in which the locust 
eggs were laid. The stout, small-headed, smooth, apod, recurved, yellowish 
white, Bombyliid larve, which attain to the length of about three-quarters 
of an iuch, were first detected amongst the locust-eggs as early as April, 
but not generally until August. ‘The ground that was first filled with 
locust-eggs by the idipoda atrow, at the end of September looked as if 
scattered with loose shells, so thorough was the work of destruction.” 
When full-fed these larvee hybernate, either in cocoons or cells of their own 
making or in the empty egg-cases, and do not change to pupe until the 
following spring. The pupal state lasts but for a short time. Mr. W. C. 
Lemmon, of Sierra Valley, California, reports, “The white grubs ate 
out and destroyed thousands of eggs last fall, but, to all appearance, 
have eaten nothing since, having lain dormant all the winter, and 
being now (June 18th, 1880) found still among the eggs, which are fast 
hatching out.” 
Within the last few days several specimens of the flies developed in the 
Troad have been received from Mr. Calvert, confirming the suspected 
Dipterous character of the locust-egg feeding larve from that locality, and 
showing the perfect insects to belong to the Bombyliide, but differing from 
any of the North American species referred to above. ‘These specimens 
were accompanied by the following details, in a letter to Sir Sidney 
Saunders, dated the 14th of June :— 
“Since writing to you, the following have been the results of my 
observations on the parasite. On the 24th of April I examined the larve 
in the ground; the only change was a semitransparent appearance which 
allowed of a moveable black spot to be seen in the body. On the 8th 
June about fifty per cent. of the larvee had cast a skin and assumed the 
pupal state in their little cells; the colour yellowish brown darkening to 
grey in the more advanced insect. About one per cent. of the cells, in 
which were two skins and with an aperture to the surface, showed the 
perfect insect to have already come out of them. A grey pupa I was 
holding in my hand suddenly burst its envelope, and in half a minute on its 
legs stood a fly! thus identifying the perfect insect. It is not the Hpicauta 
