﻿EXPERIMENTS IN MALARIAL TRANSMISSION. 521 



has laterally one or two pectinate bristles, diminishing in size toward the anal 

 extremity. 



Cluuiotaxy of the full grown larva. — In order to avoid confusion the arrange- 

 ment of the hairs on one side of the median line is given. 



Head (PI. II, fig. 1). — At the base of the clypeus, projecting anteriad over 

 and to end of the brush, is 1 straight, simple bristle, slightly to one side of the 

 median line; postero-mediad to the base of the antenna 1 straight pectinate bristle 

 and 2 more in a transverse line mediad to it and equidistant; exteriad and 

 ventrad to the antenna, curving anteriad, is 1 pectinate bristle; ventrad to this 

 is a group of 3 short, straight hairs of equal size projecting from the same 

 point ; posteriad to this another group of 3, antero-ventrad to the simple eye 

 and slightly remote therefrom ; anteriad to the median angle of the compound 

 eye-spot is 1 simple bristle projecting at a right angle to the surface of the 

 head; there are no hairs or bristles on the ventral surface. The maxillary 

 palpus is armed with a compound, palmate-pectinate bristle at the outer side 

 of the apex, before the articulation of the terminal joint. ( Plate II, fig. 3. ) 



Tkoraw. — On the anterior face (PI. Ill, fig. 2) laterad to the point of articula- 

 tion of the head is a very small, hi- or tri-furcate bristle projecting anteriad; 2 

 long bristles in a transverse line on the anterior area of the dorsum, laterad of 

 the median line ; laterad of the exterior of these and distant from it three times its 

 distance from the interior bristle, is a short, stout, pectinate bristle projecting 

 anteriad ; exteriad to this is another, more slender, nearly twice as long, projecting 

 parallel with it, the latter followed laterad by a slender, simple bristle of its own 

 length, projecting latero-anteriad; latero-ventrad to this is a pectinate bristle 

 nearly twice its length, projecting latero-anteriad; ventrad of this is a curved, 

 pectinate bristle projecting anteriad on the anterior face of the thorax; at the 

 intersection of an imaginary transverse line through the middle of the thorax and 

 one a little more than midway between the median line and the dorso-lateral 

 margin, is a long, pectinate bristle projecting antero-laterad ; laterad of this are 

 2 small, simple bristles and exteriad to these, 4 others, the most ventral of 

 which is quadrifurcate ; on the posterior lateral or metathoracic area are" 4 

 curved pectinate bristles, all twice the length of those on the anterior or 

 prothoracic area of the thorax. These bristles are all movable by means of 

 voluntary muscles. The most ventral bristle has a small pseudopod at its origin. 

 (PI. Ill, fig. 3.) The same is true of the most ventrad of the anterior or 

 prothoracic bristles and of a similar one medio-latero-ventrad on the mesothorax. 



When a larva is examined ventraliy it will be seen that the pseudopod a 

 occupy a position relative to the six feet of a coleopterous or lepidop- 

 terous larva, a pair on the pro-, nieso- and metathorax respectively. 

 They are located on prominent, tumescent tubercles and are all capable 

 of a slight motion in conjunction with the pectinate bristles. The 

 middle and posterior pair are the only ones which show signs of articu- 

 lation, each pseudopod being composed of two segments, not only visible 

 in the living larva but also in the exuviae and in macerated specimcnls. 

 I am thoroughly convinced that these organs represent atrophied or degen- 

 erate organs of locomotion, not only because of their morphology, but 

 also from their function, as observed in the living larva when it crawls 

 over vegetation, or upon a rough, moist surface. I do not recall that 

 any previous author has mentioned these organs and I call attention to 



