J. Hknnie 117 



this female when found indicated that oviposition had previously 

 taken place. A female Pachyrhina histrio taken in the open contained 

 259 black shelled ova. 



The egg measures 1-1 nim. x •4 mm.; it is black in colour, with 

 a dark purplish metallic lustre. As development proceeds this lustre 

 diminishes, and finally before hatching the shell is of a dull black colour. 

 The covering of the egg is a strong tough membrane, which is completely 

 formed around the egg before copulation takes place. I have been 

 unable to detect a micropyle, but this may be present. It is possible 

 that the membrane before coming in contact with the air is permeable 

 to the spermatozoon. The somewhat remote possibility of partheno- 

 genesis taking place with the first brood of eggs has not been overlooked, 

 and females have been kept apart from males from the period of their 

 hatching until death, but oviposition never took place under these 

 conditions. 



The Early Larva. 



The emergence of the larvae takes place in about 14 days after the 

 eggs have been laid. They are then of a pale reddish sandy colour, 

 and about 27 mm. in length, Plate XIX (6). When fully extended, 

 thirteen body segments can be made out. On each of these from 

 the third to the twelfth there is a small tuft of laterally placed, 

 moderately strong bristles. The thirteenth segment which bears the 

 spiracles and terminal papillae, has a pair of tufts of relatively stronger 

 and longer curved bristles, borne alongside the large lateral conical 

 para-anal papillae. These tufts constitute the most striking difference 

 between the early larva and the later form. 



Through the skin the two longitudinal tracheal trunks are visible, 

 and also the alimentary canal with its four anteriorly and one posteriorly 

 placed diverticula. The masticatory apparatus is well developed, both 

 mandibles and first maxillae being strongly toothed. 



In a short time the segmental bristles tend to become very short or 

 worn away, and so also do the anal tufts. Traces of the lateral bristles 

 persist even in the fully formed "grub," but the anal tufts disappear 

 completely. These changes appear to come about by attrition. In 

 about 12 to 13 days from the time of hatching the larvae are 4 — 5 mm. 

 in length when fully extended, and already resemble the older and more 

 familiar "leather jacket."' By about three weeks they have attained 

 a size of 6 mm. They feed from the first day onward. 



Ann. Biol, ni . 8 



