THE PKAR THRIPS. 



9 



incision, of the head with its bright red eyes. Little l)y httle, and 

 swaying backward and forward, the larva forces itself out until about 

 one-half of the body is exposed, when first the antenna> and then 

 one by one the pairs of legs are made free from their resting ])()sili()n 

 against the body. Swa^dng backward and forward, with legs and 

 antenna^ waving frantically about, the insect pushes out of the e<i;f!^ 

 cavity almost to its full length, whereupon, leaning forward it eagerly 

 takes a hold with its newly formed feet, and, with a final effort, pulls 

 itself free and walks rapidly away. From four to ten minutes are 

 required for the insect to fn^e itself from the egg. The young insect 

 is almost transparent and the green chlorophyll particles taken into 

 the stomach can be seen through the l)()dy wall. Growth is rapid 

 from the begimiing. 



A ver}' decided change takes place during the second larval stage 

 (iig. 4). In about three weeks the insect 

 reaches a size often larger than that of the 

 fully matured insect. It then ceases to feed, 

 falls to the ground, and enters the ground 

 by some crack or wormhole. It goes down 

 from 3 to 10 inches, accorcUng to the structure 

 and condition of the soil, the usual depth 

 being about 4 inches. Upon reaching a 

 secure depth, the larva hollows out for itself 

 a tiny spherical or oblong cell or it finds an 

 exceedingly small natural cavity and shapes 

 this for its convenience. The completed 

 chamber has a hard, smooth inner wall, 

 and it is about one-twelfth of an inch long, 

 or just a little longer than the insect itself. 

 The insect here spends the greater portion 

 of its life. It remains for several months 

 a quiescent, non-food-taking larva. Later 

 the pupal changes are undergone, and lastly the adult insect appears 

 before it issues forth to the tree. Larva^ collected from the grountl 

 on August 28 were active, and, strange to say, green chlorophyll 

 matter, undigested food, which had been taken into the stomach 

 several months before, was still present in their bodies. The insects 

 are scattered through the soil from near the trunk to several feet 

 from the tree. 



THE NYMPH OR PUPA. 



The writer has not been able to determine how long the nymph 

 stage (fig. 5) lasts, but it evidently extends over several weeks. 

 Nymphs in all stages of development were collected during May and 

 at intervals until the following February, but they are most common 

 during December, January, and February. The writer has gathered 



10090— Bull. <>8— 09 2 



Fig. .5.— The pear thrijis (t'uthrips 

 puri): nymph or pupa. Much en- 

 larged (original). 



