POST-EMBRYONIC DEVELOPMENT OF CULEX. aes 
The mid-dorsal region of the anterior portion of the 
thorax is transversely corrugated, and about the end of 
the fourth day of pupa life the cuticle splits longitudinally 
in this region and the imago escapes—first the thorax then 
the head and its appendages, then the wings and legs, and 
lastly the abdomen. After resting a moment on the empty 
pupal cuticle and on the suriace of the water it flies away. 
The imago hardly needs to be described, though fortu- 
nately it is a comparatively rare animal in Liverpool. In 
form it closely resembles 7ipula (the crane fly or daddy- 
long-legs), but differs from that fly in possessing a very 
large proboscis, by means of which the female, at any rate, 
pierces the skin and sucks the blood of man. 
The proboscis consists of a labrum-epipharynx, a pair of 
mandibles, a pair of maxille with their palps, a hypo- 
pharynx or ‘“‘tongue”’ (lingua), and a labium or “lower 
lip,’ with the labelle. The labrum-epipharynx is an im- 
perfect tube, being open along its posterior surface. The 
hypopharynx is a long slender plate, which, during the 
sucking operation, is appled to the hinder surface of the 
labrum-epipharynx, so as to close the slit in its posterior 
surface. The anterior surface has a median grove for the 
transmission of saliva into the wound, this, presumably, 
serving to liquefy the blood. ‘The hypopharynx of the 
male is continuous with the labium. 
The mandibles and maxille are long slender stylets, the 
maxille of the female being saw-like near the tips. Their 
palps are attached near the base, and are clothed with 
hairs which are, in the male, very large. The labium, 
the hindmost of these mouth-parts, forms a sheath enclos- 
ing all the other parts except the palps. It is clothed 
with scales hke those of a moth, and bears at the tip two 
small lobes, the labeliz. The labium represents a second 
pair of maxillz, and the labellee their palps. 
