576 PROCEEDINGS OF THE NATIONAL MUSEUM. 



filaments, no thornbearing dorsal plates, no spiracle bearing tubercles, 

 no gills. Cerci, when present, inarticulate and immovable. Holo- 

 pneustic. Spiracles annular or bifore. First thoracic spiracle plainly 

 in pre-epipleurum of mesothorax. Head porrect and excerted or 

 slightly invaginated. Labrum and clypeus present. Antennae three 

 jointed. Mandibles posteriorly without mola; decreasing in width 

 from basis to distal end, acuminate with single apex and usually 

 with retinaculum; a deep grooA^e along the cutting edge; no peni- 

 cillum. Hypostoma with its maxillary margin adjacent only to 

 cardo; postmaxillary margin adjacent to gula, and in some forms de- 

 tached as a separate " paragular " structure. Ventral mouthparts, 

 forming a compact unit, protracted or only slightly retracted; with 

 restricted, principally dorso-ventral movement. Cardo maxillae as 

 large or larger than stipes maxillae. Stipes maxillae, free, but mov- 

 able only in dorso-ventral direction. Mala maxillae extending from 

 the distal end of stipes; simple or transversally bisected. Palpus 

 maxillae with three, free joints and a low, not joint-like palpiger, 

 which is closely connected with stipes. Maxillary articulating area 

 absent. Submentum well defined. Mentum small. Labium with 

 two- jointed palpus. Ligula small, with simple, rounded anterior 

 margin. Gula as long as frons, elongate, rectangular, limited by two 

 parallel gular sutures, reaching from cardo's posterior end to foramen 

 occipitale ; no special pregular plate. Prothorax in the typical forms 

 with two well separated presternal plates and an unpaired median 

 sternal plate. Abdominal segments fleshy, plicate, without chitinous 

 shield except on the ninth, which in most forms has a chitinous, dorsal 

 cerci carrying plate. The abdominal segments often vividl}'^ colored, 

 in many forms hairy, and often with ampuUatory lobes. 



B. GENEEAIi MOBPHOLOGICAL DESCRIPTION OF THE LAKVAE OF THE NORTH AMERICAN 



CLERIDAE.' 



The body is digitif orm without ampullae or flattened subclaviform, 

 in most of the vividly colored, comparatively free living genera; 



» Several of the terms used in the present paper may be found to differ from those 

 applied by me in previous papers. In such cases the changes are based on renewed 

 comparative morphological studies, Jointly undertaken by Dr. F. C. Craighead and 

 myself on a considerable amount of adult and larval stages of different insects. This 

 revised terminology expresses our final contentions and consequently we regard the ter- 

 minology expressed in our earlier publications as canceled and not to be drawa into 

 further discussion. For explanation of most of the subsequent terms see: (1) John B. 

 Smith : Explanation of Terms used in Entomology (Published by Brooklyn Entomological 

 Society, Brooklyn, N. Y., 1906) ; (2) A. D. Hopkins : The Genus Dendroctonus (U. S. 

 Dept. Agr., Bur. Ent., Tech. Ser. No. 17, Pt. 1, 1909) ; (3) Kemner, A.: Beltrage zur 

 Kenntnis einlger Schwedischen Koleopterenlarven (Arch. f. Zool., vol. 7, pp. 2—1, 1912) ; 

 also Kemner, A. : Vira Clerlder (see tlie subsequent bibliography) ; (4) F. C. Craig- 

 head : Larvae of the Prioninae (U. S. Dept, Agriculture, Off. Sec. Rept., 1915) ; (5) 

 Alvah Peterson: The Head Capsule and Mouthparts of Diptera (Illinois Biological 

 Monographs, vol. 3, No. 2, 1916) ; (6) The Bibliography in G. C. Crampton's publication : 

 The Thoracic Sclerites of Immature Pterygotan Insects, with Notes on the Relation- 

 ships indicated. (Proc. Ent. Soc. Wash., vol. 20, No. 3, p. 60, 1918.) 



