DESCRIPTIONS OF GENERA AND SPECIES. 235 



two labia, separated rather widely at their posterior 

 ends ; where there is occasionally a third, smaller, 

 triangular labium between them, as in G. Crameri ; or 

 it may be placed between the coxse of the fourth pair 

 of legs, when it is most frequently two flexible labia 

 only; not separating widely when at rest, and not 

 surrounded by any chitinous ring. The anus is on the 

 ventral surface, not terminal. There are not any anal 

 (copulative) suckers, but the so-called genital suckers 

 are present in both sexes. 



The Immature Stages. The larvae and nymphs are 

 usually sufficiently like the adults to be guessed from 

 them. In G. Crameri, however, they are very different 

 from the adult. With regard to the hypopial stage, 

 this is usually either very rudimentary or unknown at 

 present, or else active and homopial. The rudimentary 

 hypopi of G. spinipes and G. domesticus have already 

 been fully dealt with in chap, vi, pp. 168 173. This 

 information need not be repeated here. In the species 

 upon which Haller's genus Dermacarus was founded 

 the hypopial nymph is a> stage found in full vigour and 

 activity, but it is homopial. What a homopial nymph 

 is has also been described at p. 165, and need not be 

 repeated. 



Habitat. Glycyphagi such as G. spinipes, G. domes - 

 ticus, G. plmniger, etc., are principally found in hay, 

 fodder, farinaceous substances, etc. ; but many of them, 

 e. <j. G. domesticus, are found in most dried vegetable 

 and many dried animal stores, especially in houses and 

 buildings. Indeed, it seems hardly possible to keep 

 G. domesticus out of anything in a house. The rapidity 

 with which it gets into unexpected places has led to 

 many curious errors ; it is certainly a destroyer of 

 dried insects. A considerable group are only found in 

 the nests of mammals, i. e. the mole, the squirrel, and 

 the field-mice. Those found in the mole's nest, of 

 which I have been the principal discoverer, have always 

 been found by me abundantly in the nest ; but, with 

 the exception of the hypopial nymph of G. Crameri, 



