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of its dorsal surface with a close-set row of long, slender, liattish thorns, 

 like teeth cut out of a saw-plate, curving upwards, but directed 

 obliquely forwards, and about .05 inch long ; on its sternal surface the 

 hind edge, except where it is covered by the wing-cases, which ex- 

 tend slightly beyond it, is armed with a close-set row of similar straight 

 thorns, directed obliquely backwards ; and .the entire hind edge of two 

 to eight is armed in a similar manner, except that the thorns are some- 

 what shorter, the suture between one and two being simple on the 

 dorsum. The anal thorn is composed of two thorns, each .15 inch 

 long, laterally divaricate at an angle of about 60°, but confluent at 

 base, their basal half robust and wrinkled, their terminal half slender- 

 ish, glabrous, black, and terminating in a very slender claw curved 

 obliquely downwards ; and the basal part of this double anal thorn is 

 almost as long and as wide as the eighth segment, but somewhat tapered 

 at tip. The pupa of the d differs only in being a little shorter, very 

 much slenderer, and of a pale yellowish-brown color. (From the pu- 

 pal integument.) Total length (f 1.18 inch; ? 1.30 inch. Total abd. 

 diameter d .23 inch; ? .37 inch. Oiie d ; one (supposed) ?. 



On March 28th, 1860, I found the above-described two larvae near 

 Rock Island, Illinois, in some fibrous debris contained in a hollow syca- 

 more. I placed them in a vessel containing about a gallon of the debris, 

 intermixed with which I noticed several common larvte, elateridous, 

 &c. ; and in the following July, what I have little doubt, from the com- 

 parative largeness and robustness of the pupal integument, was the ? 

 imago, came out, but by some means or other made its escape. No other 

 species of Midas exists near Rock Island, so far as I am aware, to which 

 it might be referred. The smaller larva, which pi-oved to be cT, lived 

 from the summer of 1860 till the following spring, healthy, but without 

 perceptibly growing, when I supplied him with twelve to twenty large, 

 vigorous, lepidopterous pupje, all of which were either killed by him or 

 else died a natural death, and between the middle of June and the 

 middle of July, 1861, the d imago made its appearance. From these, 

 facts I conclude that the larva of Midas is insectivoi'ous, and I suspect 

 that all dipterous larvge with pointed beaks are so, e. g. that of Xylo- 

 phagus, which occurs sparingly near Rock Island, Illinois, under de- 

 caying bark. The beaked larva of Tabanus I have already referred to. 

 If I am right in supposing the large larva to have been 9 , and if, as I 

 believe, those were the eggs of the insect itself that exhibited themselves 

 on its surface, but of which no traces were visible in the d larva, we 

 have here the only example known to me of sexual characters being 

 discoverable, without dissection, in the larva state of an insect belonging 

 to an Order where the Pupa is quiescent and the metamorphosis com- 

 plete. 



