DERMAPTERA 463 



The spine-tailed earwig, Doru acidedtnm. — In the genus Dom the 

 pygidium of the male is armed with a distinct spine (Fig. 542). 

 This species is dark chestnut-brown, with the palpi, legs, edges of 

 pronotum, and the outer two-thirds of the tegmina yellow. The 

 hind wings are usually aborted. The length of the body is 7.5 to 

 1 1 mm. It is distributed from New Jersey and southern Michigan 

 to Nebraska, Georgia, and Louisiana. 



The common European earwig, Forficida aitriculdria. — In this 

 species and in the preceding one as well, the second tarsal segment is 

 lobed and prolonged beneath the third; but tha two species can be 

 distinguished by the shape of the forceps of the male (Fig. 543). 

 The males of this species are dimorphic; in one form the forceps 

 average about 4 mm. in length, in the other about 7 mm. This 

 common European species appeared in great numbers at Newport, 

 Rhode Island, about 191 2. 



Family Arixeniidae. — This family contains but a single genus, 

 Arixenia, which, up to 1913 at least, contained but two species. One, 

 A. esau, was taken from the breast-pouch of a bat, Chetromeles tor- 

 quatus, in Sarawak, Borneo. The other, A. jacohsoni, was taken on 

 guano in a cave in Java which was frequented by bats. This species 

 occurred in large numbers crawling over the ground and on the walls 

 of the cave. The adults are very hairy, wingless, and viviparous. 

 The antennas have fourteen segments but the eyes are greatly reduced 

 with from 70 to 80 facets. The mandibles are flattened and the 

 cerci are rather long, unsegmented and curved, thus having the 

 appearance of weak forceps. See Burr and Jordan, Trans. 2nd En- 

 tom. Cong., p. 398, 1913. 



Family Hemimeridae. — This family includes but a single genus, 

 Hemimerus, which now contains eight species, hanseni (see Figure 308, 

 p. 269), bouvieri, talpoides, viciniis, advectus, vosseleri, sessor, and 

 deceptiis. These insects are small (from 8.5mm. to 15mm. in length), 

 wingless, viviparous ectoparasites on rats of the genus Cricetomys. 

 The known species are distributed throughout equatorial Africa as far 

 south as the Transvaal. The eyes are absent and the cerci are elon- 

 gated, unsegmented but not formed into forceps. The antennas are 

 well developed and have eleven segments while the legs, although 

 short and stout, are fitted for rather rapid running among the hairs of 

 the hosts. The body is broad and flattened, convex above and below, 

 and uniformly orange-ochraceous in color, and the surface bears 

 minute hairs. S?e Rehn and Rehn, Proc. Acad. Nat. SC. Phila., 

 Vol. 87, pp. 457-508, 1936. 



