194 INSECTS AFFECTING THE OEANGE. 



with a triangular spot of yellow color (pterostigma) near the margin 

 toward the tip j hind-wings smoky, hyaline ; feet yellowish, with dusky 

 tips ; length 5 mm to 8 mm (-& to &- incl O- 



These little animals are seen upon the trunks of orange trees in flocks 

 numbering from a dozen to forty or fifty individuals. They feed in 

 companies and browse upon the lichens which they cleanly remove from 

 the bark, leaving a clear space behind them. The colonies consist of 

 one or more families and include individuals of all ages, the wingless 

 young herding with the adult insects. 



The adults, although winged, do not readily take flight. When 

 alarmed the troop huddles together for mutual protection like sheep, 

 but if directly attacked, or when seized with a sudden panic, they scatter 

 in every direction and run nimbly over the bark, with which their drab 

 colors harmonize so closely that they are not easily distinguished upon 

 its surface. If left undisturbed, the herd in a short time reassembles 

 and quietly resumes its methodical attack upon the lichens. 



The eggs are oval, glistening white ; they are laid upon the bark in 

 batches of 15 to 30, deposited on end in several rows obliquely overlap- 

 ping each other, and the batch is protected by an oval, convex shield of 

 comminuted wood which surrounds and adheres closely to the eggs. 



The females watch their eggs, and as soon as they are hatched lead 

 their young ones forth to pasture. 



This delicately organized insect is fond of shade and moisture and is 

 most commonly seen in densely- shaded groves and old gardens. It is 

 not restricted to the orange, nor is it compelled to live upon plants 

 alone ; it may thrive on walls or fences, wherever lichens grow. The 

 smooth bark of the orange, when conditions favor the growth of fungi, 

 affords excellent pasturage to this Psocus and it frequently becomes 

 very abundant. 



It is hardly necessary to point out that to the extent of its feeble 

 powers this is a useful insect, and its presence should excite no alarm. 

 Psocus venosus is more distinctively a northern than a southern insect 

 and does not inhabit the extreme southern portion of the orange dis- 

 trict in Florida. The adult insects hibernate and begin breeding early 

 in the spring. 



THE ORANGE PSOCUS. 



(Psocus citricola Ashmead.) 



This is a smaller species than the preceding. Length 2.5 mm to 3 mm 

 (TOO- to TO^O inch). The color is white or pale yellow; the adults have 

 very transparent, hyaline wings. At all ages the semi-transparent 

 body shows the color of the intestinal contents, which varies consider- 

 ably with the condition and nature of the food. This consists of the 

 wax and other soft excretions of Bark-lice, of honey-dew, and probably 



