242 



Journal of Agricultural Research 



Vol. XVI, No. 9 



Table VIII shows the tendency of the first generation to produce some 

 puparia from which adults issue the same year and others that over- 

 winter and from which adults issue the following year. The species is 

 Uke P. calyptrata in this respect. 



Table VIII. — Tendency of individuals of the first generation to overwinter as puparia 



Experiment No. 



A13 

 An 

 Aio 

 A12 

 A16 

 A19 



Number 

 of pupa- 

 ria. 



Pupariujn 

 fonned. 



June 9 



. .do 



..do 



June II 

 June 24 

 July I 



Adults 

 issued. 



July 3 



May 6° 



July 3 



May 16a 

 May 60 

 ...do 



Number of 

 adults. 



I <? 2 



Number 

 of days. 



24 



24 

 342a 

 319O 



Overwintered as puparia and issued the following spring. 

 DESCRIPTION OF STAGES 



Egg. — ^The egg is pure white, waxy, and elongate, with a delicate 

 reticulated surface. This reticulation consists of rectangular areas 

 arranged about the egg in parallel longitudinal rows, giving the egg a 

 very regular and beautiful appearance. The micropyle end is slightly 

 flattened. The opposite end is rounded. Length i mm.; width 

 0.35 mm. 



First-stage larva. — The newly hatched larva measures about i 

 mm. It is translucent white in color, and the trachea and aUmentary 

 canal are visible through the integument for the entire length of the body. 

 The body is decidedly smooth with the exception of the intersegmental 

 areas and the posterior aspect of the last segment which are covered 

 with many transverse rows of fleshy locomotory spines. Anterior to 

 the mouth opening there are a pair of sensory papillae. The tubercles 

 on the posterior aspect of the last segment are not distinct. The poste- 

 rior spiracles are borne on short stalks and have single breathing pores. 



Second-stage larva. — At first the trachea and alimentary canal are 

 visible through the integument, but soon they become obscured by the 

 accumulation of fat. The whole body is minutely roughened, especially 

 so on the intersegmental areas and the edges of some of the segments. 

 This roughening is caused by transverse rows of minute fleshy locomo- 

 tory spines, as described in the first-stage larva. The pharyngeal skele- 

 ton is strongly chitinized, and the mandibular sclerite bears two well- 

 defined teeth and several smaller ones. Anterior to the mouth opening 

 are a pair of two-jointed antennae, and in front of these a pair of sensory 

 papillae. On each side of the " pseudo-cephalon " are a row of minute 

 button-like areas which extend from the mouth opening dorsad. The 

 posterior spiracles have two breathing pores. 



