Xo. 2323. LARVAE OF THE CLERIDAE—BOVIKG AND CHAMPLAIN. 589 



Bledius and Pselaphid genus Ewplectus have tarsus and one claw, 

 but the other genera of these two groups have fused tarsus and claw. 

 Eucnemids have rudimentary or no legs, but are, through TKroscus 

 derTnestoides^ which has well-developed legs, allied to the other 

 Cleroidea. 



2. VENTRAL MODTHPARTS FORM A COMPACT UNIT. MAXILLARY STIPES IMMOVABLE OB MOV- 

 ABLE PRINCIPALLY IN DOESO- VENTRAL DIRECTIONS. GENERALLY EITHER V7ITH A SINGLE, 

 OFTEN MOKE OR LESS DISTINCTLY TWO JOINTED MALA, OR, WHEN BOTH LACINIA AND 

 GALEA ARE PRESENT, WITH GALEA DEVELOPED AS THE MORE SIGNIFICANT OF THE TWO OR- 

 GANS, PALPIFORM AND BIARTICULATB ; LACINIA USUALLY TRIANGULAR AND SQUAMOSE. 

 MAXILLARY ARTICULATING AREA SMALL OR ABSENT. PKEGULAR PLATE * NOT PRESENT. 



This character excludes the Cleroidea from those Coleoptera larvae 

 which have either a free stipes with turning rotatory motion and a 

 large pregular plate, or, attached stipes, movable only in horizontal 

 plane, and usually a large maxillary articulating area. The first 

 alternative applies to a series formed by those larger Staphylinid 

 forms Vvhich are represented by genera like Philonthus or Stenus^ 

 by the family Histeridae, the Hydrophilid genus Helophorus^ that 

 Hydrophilid type Vv^hich is represented by genera like Hydrous or 

 S]jhaendium, and by the family Paussidae. The second alternative 

 applies to most Coleopterous families, but is especially worth em- 

 phasizing in reference to the small Staphylinids of the Oxytelus- 

 Tachinus-zSyntonium type, the larger Silphids of the Silpha- 

 Necrophonis type, and the Byrrhidae, all of which, in many other 

 respects, are families closely related to the Cleroidea. The small 

 Staphylinids have a single mala; the larger Silphids two malae, 

 lacinia large and rounded, galea short, barbate, and not jointed; 

 the Byrrhidae two malae, lacinia large and falciform, galea elongate 

 and more or less distinctly biarticulate. 



3. MANDIBLES POSTERIORLY WITHOUT MOLA ; DECREASING IN WIDTH FROM BASIS TO 



DISTAL END. 



This type of mandibles includes the labidomorphic, grasping, 

 mandibles, which are somewhat flattened, triangular, or falciform. 



^The term "Pregular plate" was introduced in 1909 by Dr. A. D. Hopkins (in 

 his publication on Dendroctonus) for an identical structure in adult Coleoptera (U. S. 

 Dept. Agr., Bur. Bnt... Tech. Ser. No. 17, 1909, pp. 10-19). A Kemner, in a very 

 interesting and instructive discussion on the term Hypostoma (in hJs previously quoted 

 publication pp. 2-3) describes (1912) the pregular plate as "Mental Platte," stating, 

 however, that vei-y likely " it might be a submental structure " (compare Kemner, fig. 14 

 with explanation). In the Staphylinid larvae, described by Kemner, the plate in ques- 

 tion evidently contains both submental and pregular elements and might therefore shortly 

 have been named " Submental platte " ; but in other forms, for instance the Hydrophilid 

 larvae Berosun and Helophorva (compare Schiodte's figures of these larvae), the pregular 

 plate (Kemner's "mental platte") appears clearly destitute of any submental element, 

 submentum here being present as a distinct area. Consequently the term " Pregular 

 plate " must be adopted as being both the more practical, more correct, and older term. 

 It might be advisable here to point out that it is only in the Carabids that SchiSdte ap- 

 plies the term " Hypostoma " to the postmaxillary part of what I, following Hopkins (not 

 Schiodte, as Kemner states), term Hypostoma. In all other descriptions Schiodte applies 

 this term Hypostoma indiscriminately to Submentum and Gula. When submentum and 

 gula (or pregula) are fused, Schi8dte mentions this joint formation as Hypostoma ; 

 when they are separated, he makes a distinction l>etween the Antei-ior and Posterior 

 Part of Hypostoma, never using the terms Submentum and Gula. 



