212 NATURAL HISTORY OF ARTHROPODS. 



jointed tarsi and double nails, and placed nearer the sternal middle than the other 

 two pairs, which are much longer and have longer four-jointed tarsi, also tipped with 

 slender double nails. The head is large, somewhat quadrate, with a flat clypeus 

 broadly rounded in front, and four-jointed antennae, behind which are two profound 

 reniforai impressions armed with a row of comb-like teeth. The rostrum is three- 

 jointed, nearly as long as the head, and has slender bristles extending throughout its 

 length. The prothorax is large and transverse, and behind it are placed a pair 

 of large scales, like rudimentary hemelytra. All parts of the body are well differen- 

 tiated, and the tranverse sutures both above and beneath are fringed with teeth or 

 stout bristles. 



Only one genus, Polyctenes, has yet been placed in this family, and it is only repre- 

 sented by the two species alluded to above. It may be recognized by the antennae 

 being longer than the head, composed of four joints, of which the first is angular at 

 base, with one long bristle above and many bristles beneath. The rostrum has three 

 joints and is dilated at base, and the tarsi are furnished on the end with a spinous 



cushion. The name was suggested by the rows of long, 

 flat spines with which they are armed beneath the head. 

 The first of these species is the P. fumarius, 

 which may be distinguished by the rounded clypeus, 

 the head with two oblique impressions and prominent 

 posterior angles ; slender antennae; a transverse thorax, 

 with the sides a little rounded, and a long bristle in 

 each angle behind ; the hemelytra nearly quadrangular 

 rind armed with bristles on the posterior angles ; the 

 sides of the body nearly parallel ; the legs with long 

 bristles, and the nails of the posterior tarsi not very 

 deeply cleft. It is about two-twelfths of an inch in 

 length, and lives in Jamaica upon the bat JMolossus 



FIG. 293. Polyctenes fumarius. 



fumarius. 



Another species, the P. molossus, infests bats of the same genus in the vicinity of 

 Amoy, China. It has shorter and thicker antennae than the other, and the basal joint 

 is armed with groups of strong spines; the posterior angles of the head are not 

 produced, but the sides of the clypeus and the surface each side of the rostrum are 

 likewise armed; there is also a curved double transverse series of flat spines on 

 the trabeculae behind the antennae, and a fringe of longer ones on the hind margin; 

 the pi'othorax is bean-shaped, armed on the posterior edge with short spines, and both 

 the hemelytra and legs, as well as the abdomen of the female, are invested with 

 short bristles. The legs are also stouter than in the other form. It is of the same 

 length as the preceding, but is a stouter and more heavily built insect. 



So remarkable and numerous are the various details of structure in this group of 

 little creatures, that whole books might be devoted to an enumeration of peculiarities 

 which would make them objects of wonder if they were of larger size. For further in- 

 formation, the reader may be referred to the beautiful iconographies of Piaget, Nitzsch, 

 and Denny. 



SUB-ORDER II. - - HOMOPTERA. 



This grand division of the order contains the greatest number of large species, 

 and the widest range of diversity in the forms of all stages. Comparatively few are 



