PUTNAM ON PULVINARIA INNUMERABILIS. 307 



gin ; one on each of the lobes of the seventh segment is larger than the 

 others and bent at the ends. The legs, antennte and otiier organs show 

 no apparent changes except an increase in size. The waxy coating now 

 becomes increased in thickness, and a series of tine pores lying in the 

 groove between each of the spiracles and their spiracular spines begin to 

 secrete a small quantity of white waxy substance. 



Up to this period there appears to be not the least observable differ- 

 ence between the larvae whi'ih become males and those which become 

 females. But soon the differentiation begins to take place and pro- 

 gresses gradually. From this time forward the lives of the two sexes 

 are as different as if they belonged to different orders of insects instead 

 of to the same species. 



DEVELOPMENT OF THE MALE PUPA. 



Those larvae destined to become males can soon be easily recognized, 

 as follows : The length becomes considerably more than twice the 

 breadth ; the sides are nearly parallel, or at least not wider behind than 

 before ; the dorsal surface is very elevated, strongly carinated, and cov- 

 ered with a very thick coating of whitish wax. traversed by many irreg- 

 ular cracks as shown in tig. 27. Tiie spines on the larval scale in the 

 specimen from whicli this figure was drawn show conclusively that the 

 males as well as the females are developed from larvse of the form shown 

 in tig. 26. 



At this time, the larva has laid up a considerable quantity of food 

 globules, and ceases to increase further in size. The pupa begins to 

 form witliin the larval skin, new antennae and legs begin to bud out 

 and develope gradually, and the first indications of wings appear. The 

 large flattened lobes of the seventh abdominal segment become changed 

 into prominent conical projections, while the " anal valves" (or the bases 

 of the anal set® of the larva) are contracted into small tubercles. The 

 ninth segment becomes transformed into a small triangular piece, 

 turned riglitside out, and is gradually elongated until it forms the style- 

 like penis. Very slight traces of the large dorsal and ventral eyes be- 

 come gradually visible, in the shape of clusters of pigment granules, but 

 they are never so proninent as in the pupa of Aspidintus. The buccal 

 sette of the larva persist for some time and probably supply the pupa 

 with food during the earlier stages. What finally becomes of them I do 

 not know, for I have not seen any signs of them under the scales after 

 the male had come out. 



The appendages grow gradually in size and definiteness of form until 

 their full development is reached. The separation of the head from the 

 thorax and all other changes take place in an equally gradual manner. 

 The pupa also gradually decreases in size, nearly if not quite as much as 

 shown in the engravings, figs. 27 to 30, 



The pupa is covered with a thin transparent pellicle which incloses all 

 the limbs and appendages. Tliis appears to me to be a waxy secretion. 

 at least it shows no apparent structure. Fig. 23 represents ihis pellicle 

 slipped half way off. 



