628 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. 51. 



pressed against each other, resulting in a very effective closmg of the 

 trachea. 



There are in all, four larval stages; the second and third agree in 

 general with the fourth stage here described, but the first larval stage 

 presents a few deviations. The head of this first stage larva is com- 

 paratively larger than in the later stages, the body is more slender 

 and the legs comparatively longer; but the most interesting differ- 

 ence is found in the last joint of the maxiUary palpus, which relatively 

 is more than twice as long as in the mature larva, and in the cranium 

 being uniformly black with a trifurcated white pattern indicating the 

 two frontal sutures and the epicranial suture. Otherwise this first 

 larval stage agrees with the last larval stage in the stmcture of the 

 mandibles, the hypopharyngeal bridge, the number of ocelli, and the 

 arrangement of the body areas. 



SYNOPSIS OF THE LARVAE OF THE COCCINELLIDAE IN UNITED 

 STATES NATIONAL MUSEUM. 



The larvae of the family CoccinelUdae exhibit a great variation of 

 structure. They can, however, only be confused with certain larval 

 types of the family Chrysomehdae, which they resemble in general 

 shape and in the development and arrangement of the chitinous 

 plates and spines of the body areas. Except the very deviating her- 

 bivorous larvae of the Epilachnini the rest of the Coccinelhd larvae 

 may definitely be separated from those of the Chrysomelids with 

 which they may be confused by the following differences in the struc- 

 tures of the head and mouth parts. 



In the Coccmelhdae the mandible is sickle-shaped with the base 

 enlarged and (except in the small genus Microweisea) with a retinac- 

 ulum present; a hypopharyngeal bridge is developed. IntheChrys- 

 omelid types referred to, on the other hand, the mandible is broad 

 with base not especially enlarged and without retinaculum; the hypo- 

 pharyngeal bridge not developed. All the Coccinellid larvae exam- 

 ined by the writer possess three oceUi, while in the Chrysomelidae 

 the number of eyes varies from none to six. It has been maintained 

 that the larvae of the family CoccinelUdae could be definitely distin- 

 guished by two depressions on the middle of the frontal suture, but 

 our knowledge of these structural details is too limited to definitely 

 estabUsh them as a family character. 



The Hyperaspis larva described above represents the primitive 

 type of the Coccinellidae, while the CMlocorini possess the most 

 highly developed larvae; between these two extremes is found a 

 series of intermedian forms ; the Epilachnini and the Psylloborini are 

 branches from the main stem with biological adaptations, such as 

 specialized mandibles (in both of the groups), and reduction of the 

 hypopharyngeal bridge (in the Epilachnini). 



