LAEVAL FORMS OF COLEOPTERA 



Last abdominal spiracle much larger than the others 



Lyctidae (pi. 102 F-K) 



S. CHRYSOMELOIDEA 



Key to Families and Subfamilies 



1. Mandible simple, distally either with a broad, transverse, 



goiigelike cutting edge, or with a simple apex 2 



Mandible dentate, distally with from two to five teeth 5 



2. Prementum and mentum fused, bearing a common, median, 



escutcheonlike sclerome with a pair of light, circular areas 

 anteriorly. (Labial palpi either (in Pachymerinae) rudi- 

 mentary, one-jointed, and placed in the light, circular areas 

 of the escutcheon (pi. 103 D), or (in Bruchinae) completely 

 absent ; mandible short, strong, gouge-shaped, with rounded, 

 distal edge ; body curved and plump ; legs vestigial except 

 in the first larval instar (pi. 103 X). Ocelli three in Pachy- 

 merinae, one in Bruchinae) 



Bruchidae (=3Iijl(thridae) (pi. 



103 A-N) 



Prementum and mentum without escutcheonlike sclerome. 



(Labial palpi present, except in a few Halticinae as Diholia 



and Spliaeroderma (pi. 114 H, and N)) 3 



3. Legs present and fully developed ; body curved and plump. 



(Mandible with excavated inner side and single, pointed 

 apex ; prementum distinct and covered with an unpaired 

 subtriangular sclerite ; mentum distinct, free laterally ; labial 

 palpi inserted well apart)... Sagridae (pi. 104 A-H) 

 Legs absent; body straight. (Leaf miners with distinct ninth 

 abdominal segment) 4 



4. Prementum and mentum not fused ; labial palpi inserted well 



apart at the base of ligula ; mandible with excavated inner 

 side and single, pointed apex 



Orsodacnidae-Orsodacnmae (pi. 

 105 A-E) 

 Prementum, mentum, and submentum fused ; labial palpi close 

 together ; ligula absent ; mandible with transverse, approxi- 

 mately gouge-shaped, and slightly scalloped distal edge 



Orsoducnidae - Z e iKj p horin a e 

 (pi. 105 F-H) 



5. Spiracles of eight abdominal segment biforous, terminal, and 



projecting like a pair of spurs. (Mentum free laterally and 

 fused posteriorly with submentum ; galea and lacinia 

 adapted for sucking of plant juice ; larva club-shaped and 

 curved, feeding on submerged parts of fresh-water plants 



and swamp plants) Donaciidae (pi. 106 A-R) 



Spiracles of eighth abdominal segment not projecting like 



spurs 6 



63 



