some British Guiana Hymenopera. 319 



I cut out tlie cane-shoot and took it home. I could not 

 examine it till next morning (13th), when I found it con- 

 tained a caterpillar, and in the same tunnel with it was 

 the egg of the parasite. It is about 3 mm. by about 1 mm. 

 at the widest part — whitish, translucent, firm or leathery — 

 narrow, elongated, tapering to a long point posteriorly, 

 where there is a small curved blackish hook. The hook 

 at the end is evidently for the purpose of keeping the egg 

 in place. From the above it seems that the caterpillar 

 is paralysed by the parasite at the time of oviposition. 

 From observations made on previous occasions, however, 

 it would appear that paralysis does not, or at least does 

 not always, occur immediately, but comes on gradually. 

 The firm texture of the egg prevents it from being injured 

 should the caterpillar happen to wriggle against it. At 

 3.30 p.m. on the same day (13th) I observed that the egg 

 had hatched and that the young larva was peacefully 

 feeding, attached to the side of the ninth segment of the 

 caterpillar. It had probably hatched during the forenoon. 

 The egg-period is therefore very short — about one day. 

 On the morning of the sixteenth the caterpillar was dead, 

 almost the whole posterior half having been devoured by 

 the parasite larva. By the morning of the 17th the 

 parasite larva had completely devoured the caterpillar, 

 and was spinning a cocoon in order to pupate. The 

 larval period, too, is very short — about four days. The 

 shortness of both the egg and larval stages can be very 

 readily understood, when it is remembered that the larva 

 requires fresh food, and has only a single caterpillar on 

 which to feed. It of necessity therefore has to get through 

 it rapidly, before extreme decomposition is reached, and 

 do all its growing in that short time. The larva pupated 

 at the angle between the shoot and the glass jar. It left 

 the tunnel, probably on accoui^t of the latter shrinking 

 through drying of the shoot. From other observations I 

 know that the larval period is sometimes certainly a week. 

 On the morning of the 31st the perfect insect emerged. 

 Pupal period therefore about fourteen days. Time from 

 egg-laying to adult is therefore about nineteen days." 

 The cocoon is transparent and constructed of closely 

 woven silk, giving a membranous appearance. In shape 

 cylijidrical, blunted at both ends. Colour whitish. Length 

 2"1 cm., diameter "-i cm. 



/. obscuricarinaius, Cameron. Issororo, N.W.D. 



