4 ARKIV FÖR ZOOLOGI. BAND 5. NIO 12. 



There are numerous hairs on the upper side of the liead, 

 several of which are of conspicuoiis length and evidently 

 are tactile hairs. They are placed as follows: near the posterior 

 margin there is a träns verse row of two pairs; further forward, 

 at the anterior margin of the vertex, there is another trans- 

 verse row of two pairs, and on the genae we notice two pairs 

 which are very finely pointed and nearly twice as long as 

 the other. The space between the anterior vertex hairs and 

 the basis of the labrum, the clypeal portion, has 8 pairs of 

 hairs, the three lateral pairs of which are the longest. 



Textfig. 1, Head of l^t larval stage, front view. X 100. 



The antennse (Figs. 3 & 4 Pl. I) are greatly reduced and 

 placed remarkably far backward. They appear as circular 

 pores with raised walls, in which a blunt, hair-hke appendage 

 is inserted; the ridge which surroundes the pores has small, 

 radiating spinules which seem to be mere modifications of the 

 small conical nodules of the cuticle. 



Eyes (Textfig. 1) There are three pairs of small ocellse 

 with red pigment, arranged in a triangle far backwards at 

 the broadest part of the head. 



The mouthparts. 



The labrum is weakly chitinized, soft and indistinctly 

 demarcated at its base; it is nearly twice as wide as it is 

 long and slightly convex anteriorly in the middle. It projects 

 forward beyond the tips of the mandibles, which consequently 

 are completely hidden underneath. 



The mandibles (Fig. 10. PL I.) are edentate, falciform, 

 as long as they are wide at the base and have curved and 

 sharply pointed tips; the median edge rises proximally to 

 a low and blunt but wide molar. 



