4 THE STUDY OF INSECTS 



Order PEDIPALPIDA 



The II 7/ ip -scorpions 



These strange creatures are found in our country only in the extreme 

 southern part for they are tropical animals; but they are distributed 

 from the Atlantic to the Pacific. In their general form they bear some 



resemblance to the scorpions; but 

 they can be easily distinguished from 

 the scorpions by the form of the first 

 pair of legs and of the post-abdomen. 

 The front legs are greatly elongated 

 (Fig. 7) and have the tarsi broken 

 up into many small slender segments 

 giving this part of the leg a whip-lash- 

 like appearance. In addition, the 

 members of one family have the 

 caudal end of the abdomen furnished 

 with a slender, many-segmented ap- 

 pendage resembling a tail. These 

 forms are known as the " tailed whip- 

 scorpions" (Fig. 7). There is, how- 

 ever, but one species of this family 

 in the United States, the giant tailed 

 whip-scorpion, Mastigoproctus gigan- 

 teus, which, when full-grown, attains 

 a length of from four to five inches 

 (Fig. 7). Its bite is said to be poison- 

 ous but direct, authentic evidence of 

 its supposed venomous quality is lack- 

 ing. This species burrows in sand 

 under logs or other objects lying on the ground ; it doubtless feeds on any 

 insects that it can capture. 



There is another family of these creatures known as the tailless whip- 

 scorpions because the individuals lack the tail-like appendage of the ab- 

 domen so conspicuous in the tailed species. The front legs, however, of 

 these tailless forms are even more whip-lash-like in appearance than those 

 of the giant whip-scorpion but the body is relatively shorter and broader. 

 There are only four species of this family found in this country and these 

 are in the extreme South. They are smaller than the giant whip- 

 scorpion. 



There is a third family represented by a single species in the United 

 States Trithyreus pentapeltis, which is less than one-half an inch in length. 

 It lives in the desert regions of Southern California. 



Fig. 7. — Mastigoproctus giganteus. 



Order SCORPIONIDA 



The Scorpions 



The scorpions (Fig. 8), have the body divided into a compact, un- 

 segmcntcd cephalothorax, and a long, segmented abdomen. The ab- 

 domen is divided into two portions: a broad pre-abdomen, consisting of 



