Contribution to the life history of Orina tristis. 253 



The full-growu larva has the general aspect and structure 

 of Orinas, as described (Ent. Soc. Trans., 1901, p. 18). The 

 thorax is relatively smaller than in some other species, and 

 looks even less than it is, by comparison, being of the same 

 dark colour as the rest of the dorsum, without any kind of 

 paler tinting. The colour of the dorsum is black with a 

 bronzy shade, due either to texture and polish, or also 

 perhaps to a certain amount of the olive or brownish tint 

 that appears laterally and predominates ventrally, declaring 

 itself in the finer depressions of the minute wrinklings. 

 These wrinklings are apparently the same as in the other 

 species described. They are generally in transverse lines, 

 each elevated line being somewhat broken by partial or 

 complete sulci in more or less diagonal directions which are 

 sometimes independent, but are sometimes the transverse 

 sulci anastomosing. So far as it is possible to count them, 

 there are about thirteen or fourteen transverse ridgfes on 

 each segment. The transverse depressions, which are 

 most marked about the fourth or fifth abdominal segment, 

 and indicate subsegmentation of the segments, and 

 varied somewhat in each species previously described, are 

 well marked, and are probably characteristic. They smooth 

 out nearly completely in some attitudes. Dorsally it is 

 about central, the anterior margin highest. Rather lower 

 than half-way down to the spiracle, it sends back a branch 

 from its anterior margin, that fades out before reach- 

 ing the dorsum. The spiracle is a minute raised ring 

 surrounded by a small smooth surface; just below this is 

 a very definite diagonal groove, passing backwards and 

 ventrally. In certain attitudes the dorsal subsegmental 

 groove passes down as little more than a fine line in front 

 of the spiracle, and seems continuous with this diagonal 

 groove. This diagonal groove is in fact the demarcation 

 between the spiracular and subspiracular fiange. The 

 segmental incision in the subspiracular flange is double, a 

 sulcus from below passing up behind one descending from 

 the dorsum. The marginal (3rd) flange is simple, its 

 upper and lower grooves being longitudinal. 



The colour of the lower surface is yellowish-brown, over- 

 laid by a clouding of small blackish spots. The head and 

 prothorax has a tolerable coating of fine brown hairs; these 

 have to be looked for, the surface having at first glance a 

 glabrous aspect. After they are seen, one decides that the 



