IOWA ACADEMY OF SCIENCES. 133 



the species could be distiuguished. Many of the galls contained more than 

 one larva. Some of the typical P. c. mamma galls were two-celled. Others 

 had a large cell in the normal position, and three or four smaller ones 

 located just above the normal one and around the cup-like depression. In 

 one or two cases five were found, six being the highest number ever found 

 in one gall. 



After the latter part of August the changes in the larva were more rapid 

 the abdominal spines are more rapidly developed, and a short time before 

 changing to the adult stage the larva produces a white cottony substance 

 which is quite abundant on the posterior portion of the abdomen. They 

 also undergo one moult a short time before sawing through the gall. This 

 is quite certain, for cast skins have been found wiih the larvai. 



THE EGGS. 



The eggs are oblong-oval, being widest at the middle, where they meas- 

 ure about .15 mm. Their greatest length is about .3 mm. They are 

 broadly rounded at one end, but taper more strongly at the other, thus giv- 

 ing the eggs a pointed appearance. When deposited on the leaf they have 

 a white, glistening appearance. The first eggs were found May 5th, and the 

 first larvte May 27th. Judging from this, in a general way, it is safe to say 

 that the eggs hatch iu about twenty to twenty-two days. 



The Larvce. — Soon after hatching the young larva? measure about .15 

 mm. in length and about the same iu greatest width. The head and the 

 divisions of the thorax can be but faintly recognized. The abdomen is 

 drawn cephalad, so that only the tirst segment is visible for its full width, 

 and only the tip of the seventh and the small eighth or anal segment. The 

 antennas are invisible at first: tarsi, two-jointed, but very indistinct; claws 

 represented by two very small bladder-like bodies. As the larva grows 

 older, the antennas make their appeai'ance, at first showing but four joints. 

 The compound eyes soon become largei', and the abdomen develops so that 

 five of the segments are visible. The posterior end of the body now pre- 

 sents a lobed appearance, because the last three segments are very small, 

 and drawn cephalad, pushing the central portion of the tirst five segments 

 forward, while the sides extend backward, forming a lateral lobe on each 

 side. The lines separating the abdominal segments are most clearly seen 

 on the dorsal surface. In some cases they do not reach the sides as closely 

 defined lines, but seem to terminate in little circular, transparent spots, 

 probably representing the division between the tergum and the pleurum. 



From June 1st to June 22d, no very marked changes, except in size, 

 take place. The last three abdominal segments are very slow to develop. 



The larvfe examined August IGth showed some important changes. The 

 antenna? increased iu comparative length, having from six to ten joints. 

 The compound eyes more prominent, mouth-parts larger, and the different 

 divisions quite distinct; legs much larger, more prominent and furnished 

 with numerous hairs. The two joints of the tarsi are quite inconspicuous, 

 the strong curved claws apparently being attached to the distal end of the 

 tibia rather than the tarsus. The two pairs of \\ing8 have begun to develop 

 and appear as small transparent pads arising from the mesothorax and the 

 metathorax respectively, and are immovable. The divisions of the sternum 

 are quite distinct, and the coxiv much more prominent. The abdominal 

 segments are all closely defined; the last three, however, are quite closely 



