LARVAL FORMS OF COLEOPTERA 



4. Eighth abdominal segment glandular, discoidal, and terminal. 

 (Ninth and tenth abdominal segments minute, leg three- 

 jointed) Paussoidea (p. 24) 



Eighth abdominal segment not glandular and not discoidal 5 



, 5. Urogomphi jointed,*^ individually movable. (Often retracted 

 into a terminal breathing pocket in eighth abdominal seg- 

 ment in the Hydrophilidae) 6 



Urogomphi solid or absent 7 



6. JMaxillary palpiger as a rule closely connected with stipes, not 



often carrying a finger-shaped galea ; spiracles annular. 



Staph ylinoidea (p. 25) 

 Maxillary palpiger free and joint-like, usually carrying a fin- 

 ger-shaped galea; spiracles biforous Hydrophiloidea (p. 31) 



7. Hypermetamorphosis present; mandible without molar part; 



maxillary mala short, thick, almost vestigial ; gular area pres- 

 ent ; spiracles annulif orm and often large ; urogomphi ab- 

 sent*^ Meloidea (p. 58 ) 



No hypermetamorphosis ;^° different combination of the five 

 mentioned structural characters 8 



8. Larva with mandible bearing an accessory ventral condyle and 



with either a free galea well separated from a distinct lacinia 

 or with cribriform spiracles, or with both of these charac- 

 ters" 9 



Larva with a different combination of the characters. (A man- 

 dible with an accessory ventral condyle never occurring to- 

 gether with either a free galea or actually cribriform spir- 

 acles) 10 



^ Absent in some Pselaphidae, Scydmaenidae. termitophilous 

 Histeridae, and the later instars of parasitic Staphylinidae. 



^ First larval instar, often named triungulin, triungulinid, or tri- 

 unguloid, has frequently a pair of setae at the end of the body, and 

 in one subfamil}' is the eighth abdominal pair of spiracles placed 

 on projecting hooks or warts ; the legs have a single, frequently spat- 

 ulate claw which is provided with one or two setae at the base or at 

 the luiddle, these setae so large and strong in many genera that they 

 appear as extra claws and for a long time were considered as such ; 

 hence the name "triungulinus. " Apparently three-clawed legs 

 have occasionally been found in larvae of other series, for instance, 

 in an undetermined lamp^'rid larva. 



^° Drilus has polymorphic metamorphosis and some members of 

 the family Cantharidae have, according to Verhoeff, foetometamor- 

 phosis, that is, two free embryonic instars preceding the first larval 

 instar. 



" Accessory ventral condyle absent in the family Passalidae 

 which, however, is readily distinguished by possessing atrophied 

 metathoracic legs (pi. 87). 



11 



