214 ENTOMOLOGY FOR MEDICAL OFFICERS 



Warburton has recently followed out the life history of 

 some individuals of the same species. An impregnated 

 female, kept in a tube at the temperature of the body, and 

 allowed to suck blood twice a day, produced 125 eggs in the 

 course of twenty-five days (in the month of December) and 

 then died. Of the eggs that were kept under observation, 

 some hatched in eight days, others did not hatch for more 

 than a month. The larv^ sucked blood immediately after 

 hatching, and became adult in about eleven days, moulting 

 three times during their growth ; as adults they did not 

 exercise sexual functions for four or five days after reaching 

 maturity, and they died (they were males) three weeks after 

 their final moult. Larvae not allowed to suck blood died in 

 thirty-six hours ; and adults kept from blood died in three 

 or four days. These experiments show that under suitable 

 conditions lice increase in numbers with amazing rapidity, 

 and that they cannot live long without blood as so many 

 other blood-sucking Arthropods can. 



The Siphunculata have recently been split up into families 

 and subfamilies, but the older view that they form a single 

 homogenous family — Pediculidce — seems much more reason- 

 able. The species are not very numerous, and only three 

 of them are constantly parasitic on man. 



Synopsis of Genera (j/Tediculidae. 



{Antennas of 3 segments = 2- 



Antennae of 4 segments ; integument spinose ; on Seals = 4. 



Antennae of 5 segments = 5- 



J Eyes large and well pigmented = Pedicinus. 



\Eyes inconspicuous = 3. 



Femur and tibia of hind legs with stalked platelets projecting 

 outwards at a right angle = EuhaTnatopinus. 



Hind legs normal : lateral margins of abdomen serrated 



= Hatnatopinoides. 



Abdominal segments with not more than three transverse rows of 



spines = Echinophthirius. 



Abdominal segments with six to eight transverse rows of spines ; 



dorsum with scales = Lepidopthirius. 



Legs long and slender, tarsi with two unequal claws ; head 



anteriorly tubular ; on elephant = Hamatomyzics. 



Legs short and robust, tarsi ending in a single talon = 6. 



Eyes large and well pigmented = 7. 



Eyes inconspicuous or absent = 8. 



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