SCIENCE-GOSSIP. 



It is doubtful whether the males in the larval and 

 pupal stayes are distin<ruishable from the females, 

 or are capable of ilistension. 



The head is provided with two palpi, canicu- 

 lated to enclose and protect a strongly-barbed 

 rostrum, by which suction is etTected. This is 

 flanked bv two retractile chelifers, also armed with 



?«: 



m 



Fig. I. — Rostrum, etc.. o^ Fcniak- I. rediivius. 



barbs or hooks, bv whicli the rostrum is forcetl 

 into the flesh of the host. Respiration is attaincil 

 lhrouj;h a spiracle on each side of the body, which 

 is absent in the larval stage. 



The legs are eight in number in the pupae an.l 

 adults, but there are only si.\ in the larvae. They 

 consist of six joints, of which the third of each 

 leg, and the terminal joints of the three posterior 

 pairs, possess a double articulation. The last 

 joints of the anterior pair have an organ on the 

 outer side (Figs. \a and 2a), which is probably 

 used as a feeler when the tick is resting on herb- 

 age, wailing to attach itself to a passing mammal. 

 At such times this pair of legs will be seen to be 

 constantly waved in the air, after the manner of 

 the antennae of insects. In some species this pair 

 of legs is furnished with one or more spines on the 

 lasal joint. (Figs. I A and 2/5.) Each leg has a 

 double hook on the last joint, provided with a 

 fleshy pad, or caruncle. (Fig. ic) 



The diflcrcnce of the rostrum and chelifers in 

 the two sexes is exhibited in Figs, i and 2, the 

 former of which shows those of the female, and the 

 latter those of the male. The difference of the 

 final and l>a.sal joints of the fore legs is also 

 shown. These drawings are taken from Ixodcf 

 redtn'itis. 



The specific difTerences of the lar%-ae are : — Palpi 

 not articulated. Shield covering less than one-half 

 of the body. Spiracles absent. Three pairs of 

 legs only. (?) Sexes not distinguishable. 



The pupae, or nymphs, are more developed 

 generally. They have embryonic articulation of 

 the palpi. Spiracles present. Shield covering 

 less than one-half of the body. Four pairs of legs. 

 (?) Sexes not ilisiinguishablc. 



The adult ticks are still further developed. The 

 palpi arc articulated. Sexes easily distinguishable. 



M.vLK. — Body covered bv the shield, a narrow 

 margin excepted. The organs of the mouth are 

 inserted in the female at the time of sexual pairing. 



Fem.\le. — Shield covering less than one-half of 

 the body. Orifice of sexual organ (Fig. 3) situate 

 between the bases of the fourth pair of legs. 



The larvae are easily distinguished by having 

 only six legs and no spiracles. When walking, the 

 first and third legs on one side are raised concur- 

 rently with the second on the other, giving a 

 peculiar action. 



The pupa, having eight legs, requires, apart from 

 its smaller size, careful examination to distinguish 

 it from an adult female. The chief distinction 

 (Fig. 4) is absence of orifice of sexual organ in the 

 former. The size of the shield distinguishes the 

 adult male as clearly from the female, as from the 

 immature insect. Distension, caused bv sucking 

 the blood of the host, takes place in all stages, 

 except with the adult male, and possibly with the 

 immature males. 



The exact method of pairing between the sexes 

 is doubtful, but during the act, the chelifers and 

 rostrum are inserted in the organ of the female, 

 the palpi alone being excluded. 



As adults, the males are to be found in company 

 with the females, not only on herbage, but also 



Fi|^. 2. — Rostrum, etc.. ^i M.lU- 1. rcdu\ius. 



on the host, feeding by the rostrum. This was 

 proved by several .adult individuals of both sexes 

 having pieces of the skin of the host still attached 

 to the rostra, after removal, and others having 

 the rostra mutilated by the act of removal. The 

 proportionate sizes of the various stages of growth 



