4 The Philippine Journal of Science ms 



Adult. — The only adult character that appears to be of any 

 value in distinguishing females of the two types is the length of 

 the first black palpal band. The variability of this character is 

 shown in Table I, where females are compared according to the 

 ratio that the length of the first black band bears to the length 

 of the portion of the palp covered by this band and the terminal 

 white band, or 



first black 



first black + terminal white 



All specimens included in these tables had been previously iden- 

 tified in the larval stage. 



In the smaller group under A, of Table I, palp measurements 

 were made under the low power of a compound microscope by 

 means of an eyepiece micrometer. The insects were chloro- 

 formed and, while still fresh, placed each on a slide in a definite 

 position; the palps were then covered by a small cover glass 

 in such a way as to bring them parallel to the slide. The same 

 specimens were measured by means of a hand lens without a 

 scale. The hand lens measurements are entered under B, of 

 Table I, for comparison. The line of demarkation between the 

 bands, usually definite under the hand lens, sometimes ap- 

 peared irregular under the high power. Further, terminal 

 scales that do not get their full value under the lens may be 

 included in the high-power measurement. The two sorts of 

 measurement, therefore, cannot be expected to agree exactly. 

 However, the aim was simply to compare approximately the 

 variability of the two types in regard to a certain character, 

 and in that respect the hand-lens measurement appears to agree 

 closely enough with the more accurate method to suffice. In C 

 larger numbers are included and only hand-lens measurements 

 are given. Since many of the anophelines included under C 

 were to be used subsequently for infection experiments, it is ob- 

 vious that they could be examined only in the living stage. They 

 were measured in test tubes, usually but one or two in a tube, 

 and were viewed as nearly as possible at right angles to the 

 palps. The hand-lens measurements are only approximate, but 

 as stated above, the approximate agreement of measurements 

 under A and B of the table indicate that the hand-lens meas- 

 urements were sufficiently accurate to show, in a general way, 

 the amount and character of the variability in length of the 

 terminal palpal bands of the two forms. 



