228 



COLEOPTERA 



CHAP. 



clavicorn (basal and apical joints thicker than middle joints') ; tarsi 

 three-jointed; elytra sometimes covering abdomen, in other cases 

 leaving a variable number of segments exposed ; wings fringed. 

 This family comprises the smallest Insects ; Nanosella fungi being 

 only T ^Q- of an inch long, while the largest Trichopterygid is 

 only -^2 of an inch. The small size is not accompanied by any 

 degeneration of structure, the minute, almost invisible forms, having 

 as much anatomical complexity as the largest Insects. Very little 

 is known as to the natural history. Probably these Insects exist in 

 all parts of the world, for we have about eighty species in England, 

 and Trichopterygidae are apparently numerous in the tropics. 1 



Fam. 22. Hydroscaphidae. Extremely minute aquatic Insects, 

 with elongate abdomen. Antennae eight -jointed. The other 

 characters are much the same as those we have mentioned for 

 Trichopterygidae. The family is not likely to come before the 

 student, as only three or four species from Southern Europe and 

 North America are known. 2 



Fam. 23. Corylophidae. Minute beetles. Tarsi four-jointed, 

 but appearing only three-jointed, owing to the hind joint being 

 concealed by the emarginate (or notched) second joint. Six free 

 ventral segments. Maxillae with only one lobe. Antennae of 



peculiar form. There are about 

 200 species of these little Insects, 

 but the family is apparently repre- 

 sented all over the world, and will 

 probably prove to be much more 

 extensive. The peculiar larva of 

 Orthoperus lirunnipes was found 

 abundantly by Ferris in thatch in 

 France. Mr. Matthews proposes 

 to separate the genus Aphanoceph- 

 alus as a distinct family, Pseudocory- 

 FIG. 107. A, Larva of Orthoperus lophidae. 3 In Corylophidae the 



Z, . . , , _____ /_ j"i_ i~ \ w s\ *- i/ J- 



brunnipes (after Ferris); B, 0. ato- 

 Marius, perfect Insect. Britain. 



wings are fringed with long hairs, 



as is the case in so many small 

 Insects : the species of Aplianoceplialus are rather larger Insects, 

 and the wings are not fringed ; the tarsi are only three-jointed. 



Monograph, Tricliopterycjia illustrata, by A. Matthews, London, 1872. 

 2 For further information refer to Matthews, An Essaij on Hydroscapha, London, 

 1876, 20 pp. 1 pi. 3 Ann. Nat. Hist. (5) xix. 1887, p. 115. 



