LICE AND THRIPS. 



tarsi are single-jointed, forming a claw at the end of the 

 tibia. Another scientific name for them is Parasita. 

 Three species (Plate XXI) attack man: Pediculus capitis, 

 the common Head-louse; Pediculus vestimenti, the usually 

 rare Body-louse, Clothes-louse, or Gray-back; and Phthirius 

 inguinal is, the Crab-louse which prefers the arm-pits 

 and pubic regions. Liberal and repeated applications of 

 mercurial ointment are "indicated" for the last-named. 

 A fine-toothed comb and keeping the hair greased with 

 vaseline are usually effective in killing off capitis. A more 

 suddenly effective remedy is to rub kerosene in the hair at 

 night, wrap the head in a cloth, and wash out the kerosene 

 the next morning; repeat in two or three days. Most of 

 the true lice which attack other animals, such as sheep, 

 hogs, oxen, rabbits, rats, and the like, belong to the genus 

 Hccmatopinus. 



THYSANOPTERA 



The narrow insects, usually black and rarely more than 

 .04 in. long, which are often seen in flowers, belong to this 

 order; also the Onion-thrips (Thrips tabaci) and Thrips 

 in general, some of which are called Black-flies by gar- 

 deners. The wings, if any, are very narrow and fringed 

 with long hairs. The feet are bladder-like. The mouth is 

 fitted for sucking but is lop-sided, only the left mandible 

 being developed; the head is held in such a position that 

 the mouth-parts are pressed against the under side of 

 the thorax and concealed. The young are much like the 

 adults but there is a quiescent stage, just before the 

 mature one, which is very pupa-like and during which no 

 food is taken. Some species (both sexes or only one) 

 never or rarely have wings and sometimes males are 

 absent or rare, the eggs developing without fertilization. 

 In these respects they are like aphids, for example. Some 

 species live under bark and in decaying vegetation. 



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