228 



COLEOPTERA 



clavicorn (based and ajncal joints t/iicker tlian middle joints) ; tarsi 

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

 leaving a variable number of segments exjwsed ; wings fringed. 

 This family comprises the smallest Insects ; Nanosella fungi being 

 only -j^Q of an incli long, while the largest Trichopterygid is 

 only jV 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.^ 



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.^ 



Fam. 23. Corylophidae. — Minntc beetles. Tarsi four-jointed., 

 but apj)earing only three -jointed, oioing to the hind joint being 

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

 ventrcd segments. Maxillae witlo 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 

 Ortlioperus brunnipes was found 

 abundantly by Perris in thatch in 

 France. Mr. Matthews proposes 

 to separate the genus Aphanocepli- 

 cdus as a distinct family, Pseudocory- 

 107.— A, Larva of Orthoperys lophidac.^ In Corylophidae the 



marius, perfect Insect. Britain. ^mgS are Imiged With long hairS, 



as is the case in so many small 

 Insects : the species of Aphanocephcdus are rather larger Insects, 

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



Fig. 



^ Monograi)li, Trieho2)teryrjia illustrata, by A. Matthews, London, 1872. 

 - For further information refer to Matthews, An Essay on Hydroscapha, London, 

 1S76, 20 pp. 1 pi. 3 Ann. Nat. Hist. (.5) xix."l887, p. 115. 



