HOW TO KNOW THE IMMATURE INSECTS 



41a. Maxillary articulating area either large or in- ^ 

 distinct; when indistinct, mandibles with mola 

 (except in Catogenidae, Epilachninae and Lami- ^^'^-^^ 

 inae). Fig. 220 42 



Fig. 220. Maxiilta. 



41b. Maxillary articulating area absent, or very small, or concealed by 

 mentum, not large and cushioned; mandible without molar 

 part 43 



42a. Maxillary mala divided into a well developed lacinia and a 

 finger-shaped, 1 or 2-segmented galea; mandible without a dis- 

 tinct molar part but with a longitudinal series of hairs at the 

 base. Fig. 221 Family BYRRHIDAE 



The family has about 500 species. The adults 

 are called pill beetles. Their life histories are 

 in need of study. The larvae of Bynhus pilula 

 are found beneath turf or moss. The larvae of 

 Amphicyrta dentipes are often injurious to wild 

 and cultivated plants. 



Fig. 221. a, Byrrhus 

 fasciatus Forst.; b. 

 Mandible. 



42b. Mala simple, or division either indicated by distal notch or pre- 

 sent with lobe-like galea; mandibles with or without a molar part 

 but without a longitudinal series of hairs at the base 66 



43a. Either with exposed gills below the entire ab- 

 domen, or with movable 10th abdominal seg- 

 ment usually covering retractile gills at the end 

 of the body, or with mamillaeform appendices 

 from the 10th abdominal segment; mandibles 

 never perforate or deeply cleft. Fig. 222 44 



Fig. 223. Tip 

 of obdomen. 



43b. Gills or anal appendices usually absent; when present, then 

 mandible either perforate or deeply cle|t longitudinally 48 



44a. Movable 10th abdominal segment absent 45 



91 



