ENTOMOLOGIST AND BOTANIST. 



369 



siiecics bulonging to a genus allied to Cerapterocei-its , and 2 

 species belonging to a genus allied to Coccophagva, the c<il- 

 lare, though short and transverse, is distinctly visible from 

 above, and the sutures between the mesothoracic prajscutum 

 and scutum, commonly known as the parapsidal grooves, are 

 [Fig. 8.] 



entirely obliterated, as is partially the case in Semiolellus 

 (Fig. 8, C). Figure 8, A, shows the mesouotal subsegments 

 of Antigastcr, as seen from above when depressed for flight or 

 walking. Figure 8, B, shows the corresponding parts in the 

 mesonotiun of £uri//07na, Decaioma anA hosoma; and Figure 

 8, C, those in Semiolellus. In all the three figures the coUare 

 (when visible) .ind the mctathorax are shaded to distinguish 

 them from the niesonotum ; and in the mesonotum of all of 

 them the pn-uscutum is lettereda, the scutum 6, thescutellum 

 c, and the postscutellum d; the coUare (when visible) being 

 U-ttered e. 



[Fig. 9 ] 



veins and stigmatic branch brown. Hind Wings hyaline; 

 veins pale bi-own. Length Q 0.1.^$— 0.14 inch. 



Described from 3 9 taken upon herbage near Rock Island, 

 Ills., in August and September; 2 g with the thoracic parts 

 elevated and the body more or less rolled up, the other ? 

 with the thoracic parts depressed and the body extended ; d" 

 unknown. Nothing but the almost exact coi-respondence of 

 all the complicated oolorational and stractural peculiarities, 

 found in this insect, would ever induce any entomologist, 

 unacquainted with this most remarkable genus, to believe 

 that these three specimens are all identically the same. 



Rock Island, Ills. , March 22, 1869. 



(Fig. 10.) 



[To make this paper as complete as possible, we subjoin a 

 few remarks on the natural history o! Antigaster mirabilis and 

 a description of the tf. In doing so we cannot repress a sigh 

 of regret that so cruel a fatality should have prevented the 

 master hand which penned the Paper from properly com- 

 pleting it. 



Dm-ing the month of April, im», we bred 9 9 5 <? of this 

 parasite from one batch of eggs of Phylloptm-a oHangifolia, 

 DeGeer, found near St. Louis; and 3 S from another batch 

 received from Louisiana, Mo .—thus mdicating that it is by 

 no means of uncommon occurrence in these eggs. As Mr. 

 Walsh's three Q were all eaptiu-ed during August and 

 September, we must infer that this parasite Is either double- 

 brooded, or th.it it (the Q at least) sui-vives during the sum- 

 mer nn.uths from April to September. The last hypothesis 

 is aoubtk-.ss the correct one, for if it is double-brooded it 

 must breed in some other kind of eggs than those of P. ob- 

 longifolia, which are not deposited in the latitude of St Louis 

 till the first of September, and which hatch during the fore 

 part of April. 



The larva of this little anomaly we have never seen, but the 

 pupa (Fig. 10, 6) is characteristically flattened and straight- 

 ened so as the better to adapt it to its compressed domicile. 

 The fly, after it is full fledged and well dried, gnaws an ir- 

 regular but usually round hole near one end of the egg, 

 through which to escape to the light of day; the eggs which 

 have been parasitized thus presenting the appearance of 

 Figure 10, a. 



The sexes differ remarkably, and had we not bred both 

 scMs from the same batch of eggs we should scarcely have 

 liili. V. .1 them to be at all allied. The <^ (Fig. 10, c) wlU be 

 lust .Inscribed by comparison with the Q. As will be seen 

 by glancing at the figures of the two sexes, he approaches 

 much more nearly than she does to the normal Chalcididous 

 foi-m. We believe it is a veiy general law in Chatcididce, 

 that where the Q is greenish the cf is always of a more brU- 

 liant and decided green, and our cT Antigaslertonaa no ex- 

 ception, being of a much brighter metallic green than the Q . 

 We never saw him roll up backwards as does the 5 , and, 

 from his form, do not believe that he has this peculiar power. 

 He certainly has not that nniarkable and unprecedented 

 power, which she possesses, of setting up or depressing at 

 will the mesouotal subsegments ; and he differs in other re- 

 spects as follows : 



Antigaster mirabilis, cf.— Color brilliant metallic-green 

 with faint blue and pmple reflections. Head very bright 



