26 PBOCEEDINGS OF THE NATIONAL MUSEUM. vol.64. 



cell to another as the content of honey in one cell is large enough 

 to supply the parasite with food for its whole feeding period; it 

 therefore remains as in THcrania in the same cell in which it has 

 been parasitizing during the preceding stages; but in Zonitis and, 

 according to Cros, probably also in Nemognatha the fourth instar 

 leaves its first cell and enters another, devouring the whole content, 

 bee-larva as well as honey, before it changes into fifth instar. The 

 fourth instars of the two last genera are characterized by small but 

 distinct spiracles on the eighth abdominal segment, all the other 

 genera possessing either minute eighth abdominal spiracles, as Sita- 

 ris, or apparently none, as A'palus. In Nemognatha the instar is 

 described by Cros as very curved (" fortement curvee en arc"), in 

 the other genera it is fusiform-ovate as in Tricrania. 



The chitinizations, present on the prothoracic tergum in Tri- 

 crania^ are not developed in all genera, for instance not in A'palus 

 and Sitaris; in Hornia, on the contrary, a complete, rather large, but 

 thin prothoracic shield is present. 



FIFTH LARVAL INSTAR. 



Figs. 11, 17, 18, 32, 34. 



Larva inclosed in and entirely surrounded by the unbroken and 

 not shed exuvium of fourth instar. 



Length of larva, about 10.25 mm. ; width, about 4.25 mm. ; conse- 

 quently smaller than the previous full-grown instar. 



Color, yellowish. 



Setae, none; body covered with fine asperities. 



Body, with thin, pellucid but rather rigid skin; almost regularly 

 ovoid, dorsally and ventrally convex, ventrally slightly flatter ; mouth 

 parts and legs very reduced and tuberculif orm ; segments plainly 

 indicated ; main areas distinguishable, terga transversely divided 

 into two folds, epipleural areas not forming any continuous lateral 

 ridge above the distinct ventro-lateral suture; ninth and tenth seg- 

 ments rather short, flatly rounded ; anus oval, facing downwards. _ 



Head, nutant, somewhat retracted, vaguely formed. Head-capsule 

 transversely oval ; length medio-dorsally about 1 mm., slightly shorter 

 than in fourth stage; laterally only half as long as in fourth stage; 

 width the same in both stages, about 1 mm. ; ventral side behind the 

 ventral mouth parts very short, developed as a transverse, narrow, 

 laterally somewhat enlarged band. Dorsal and ventral surfaces of 

 head slightly convex. 



Antenna, mandible, maxilla and labium, short, thick, tuberculi- 

 form, without segmentation, recognizable only by their relative posi- 

 tions. 



Ocellus, merely represented by a single, transverse dash of dark 

 pigment, somewhat larger than in fourth stage. 



