BEUTENMULLER, MONOGRAPH OF THE SESIID^E. 229 



j Alcathoe caudata. 

 Crochets well developed, normal \ ^^ sMa 



Crochets very small, reduced Bembecia marginata. 



\ ^sP'sid albicovms 

 Lower ocellus obsolete, represented by a pale spot . . . . j . 



Crochets 15 to 18 in a row ; lower ocellus obsolete ; epicranial lobes ( Sesia pictipes. 



meeting in a point < Podosrsia syringa. 



. \ Memythrus tricinctus. 



Crochets 18 to 22 in a row ; epicranial lobes broadly touching j . 



Third annulet more elevated than the others. 

 Crotchets 12-14 in a row. 



Lower posterior ocellus with a slight lens Sesia acerni. 



Spiracles black ; tubercles absent ; segments not annulate, smooth Melittia satyriniformis. 



Habits of the Larvae. 



The larvae are universally borers, but in the choice of food-plants there is the 

 widest diversity ; some bore through and devour solid wood, as do the larvae of 

 the Cossids ; some prefer the pith of woody stems ; others are found in the 

 superficial woody layers ; still others affect the roots of plants both woody and 

 herbaceous, or are sometimes to be found in the borings made by other insects, as 

 is the case with Memythrus ti'icinctus, Sesia pictipes, S. scitula, and others. The 

 larvae are yellowish or dirty white, beset with only a few short hairs. The head 

 and cervical shield are chestnut brown. They hibernate in various stages of 

 growth but do not overwinter in the pupal stage, as far as the species of the 

 northern States are concerned. The larvae of Melittia satyriniformis hibernate 

 fully grown in the cocoons. When fully developed they spin elongate oval 

 cocoons composed of chips cemented together by a gummy secretion or silk. 

 The cocoons are formed in the burrows or in contiguous places. 



Synopsis of Food-Habits of the Larvae. 



Boring in trees. 



Under bark of trunks some distance from the base or in the branches : 



Maple , Sesia acerni. 



Maple " corni. 



Apple, Pear " pyri. 



Dogwood, Oak, Chestnut " scitula. 



Alder " americana. 



Cherry, Plum, Juneberry u pictipes. 



Pine, Redwood {Sequoia) Vespamima sequoice. 



Pine and Spruce Parharmonia pini. 



Under bark at base of trunk or main roots : 



Peach, Cherry, Plum, Apricot, etc Samiinoidea exitiosa. 



Peach and Cherry " opalescens. 



Peach. Cherry " grcrfii. 



