12 AV. AVESCHE — THE LARVAL AND 



Shipley's figure 11 o£ Plate ii (/. c), and bear the two stiff bristles which, as 

 they observed, were used to clear the brushes. When the head is looked at 

 from the ventral side, the chitinised teeth can be seen in the interior of the 

 mouth, under the niaxilla3 and just above the under lip (PL II, fig, 10 ; PI. IV, 

 %. 5J. 



The Maxilla. 



These occupy a very prominent position when the mouth is looked at from 

 the under side, and are very diverse and characteristic in appearance. In 

 A)ioj)heles well deA'eloped palpi are present, but in other forms these organs are 

 much atrophied, and in Culea: caU[/inosiis, Graham, I think they are completely 

 aborted. The maxillse in this species are small, hairy and palpiform in 

 appearance. In C. dissimiUs, Theo., they are less palpiform, and have a 

 strong brush at the apex, besides rows of spines ; palpi are present, but 

 in an atrophied condition. In this species the maxillse have several short 

 claws at the end (PI. lY, fig. 4), and I have also seen these on Pectinopalpus 

 fir sea, Theo., ? (I) as very insignificant appendages to the long maxillae. 



The Labium. 



This organ may Ijc represented by the complicated structures found in the 

 heads of Cv.lex cal'ujinosus, Graham, and C. dissimiUs, Theo. 



It presents a very different appearance in the two species. In the former 

 there is a central brush of spines from which proceed paired rods which 

 curve outwards ; in the spaces between the spines and the rods are two pairs 

 of stout blunt hairs, which do not differ in appearance from the '^ taste hairs " 

 on the mouths of insects ; the parts are flanked by complicated toothed 

 plates, and have above them two longer stout blunt hairs, and a pair of 

 minute two-ended processes. The whole is very small, as at its greatest 

 width it is but jL mm. 



In Cidea: dissimiUs, Theo., the organ is dissimilar in appearance, though 

 of about the same size. In the centre is a three-})ointed process, on either 

 side of it being the four " taste hairs,'''' and it is flanked by toothed processes; 

 from the central process proceeds a short rod, which extends to an opening 

 of a hexagonal shape in a plate of complicated folds ; at the top is a curved 

 plate with spines at its outer ends (PI. IV, fig. 2). From the middle of 

 -these organs runs down the pharynx, a transparent membranous tube. 



^ear this part in C. dissimiUs is a pair of circles with transparent cilia 

 (PI. V, iig. 1), which are identical in structure with similar circles or ovals 

 found in the same portion of the head of some Isopods — such as our common 

 wood-louse (PorceUus scaher) *. 



* Miall, ^ Aquatic Insects,' p. 117, notices this organ in Corethm and Cule.v larva?. 



