SCIENCE- G OS SIP. 



7i 



for some time. It fills up the meshes more and 

 more, and afterwards follows the threads with its 

 mouth to strengthen them with additianal applica- 

 tions ; so that the cocoon in this species becomes 

 compact, with only small rounded meshes. The 

 whole work occupies about a day. Osborne states, 

 however, of H. rumicis that the spinneret is anal, 

 the silk issuing from it in a very thick transparent 

 thread. This conflict of observation is somewhat 

 puzzling, but the matter has been cleared up, fortu- 

 nately, by Perris, whose admirable observations 

 relate chiefly to H. vieiae. This naturalist failed to 

 perceive a spinneret on the lower lip, and he states 

 definitely that no such organ exists there. Yet it 

 cannot be denied that the larva spins. It spins, 

 says Perris, in the true sense of the word, and this 

 is how it proceeds. When the time to form the 

 cocoon arrives it retires to a convenient position 

 and applies the mouth to the dorsal base of the last 

 segment, where the above-mentioned organ which 

 secretes viscous matter is situated. From this 

 organ (the ejaculatory nipple) escapes a small 

 drop of matter, and the larva, having seized this 

 drop w.ith its mandibles, forthwith places its head 

 to the right or to the left on various points around. 

 The matter, adhering to these points, is drawn 

 out into threads, more or less slender, which 



are fastened and crossed in all directions. The 

 mandibles and palpi are the organs which serve 

 to draw out and fashion the threads. These 

 dry, harden, and lose their viscosity almost imme- 

 diately. After about two hours the framework of 

 the cocoon is well formed ; but the meshes are 

 very wide, and the larva still labours to make them 

 narrower, which it does by the addition of fresh 

 filaments. The whole work occupies about twenty 

 hours. Each time the little provision of viscous 

 matter is exhausted the animal has recourse to the 

 nipple, and this occurs often enough to make the 

 process easily observable. A number of the larvae 

 were induced to spin under watch-glasses. Here, 

 lens in hand, Perris had them under observation 

 for hours together ; and there is not the slightest 

 doubt as to the accuracy of his conclusions. The 

 creatures, though destitute of an oral spinneret, 

 certainly produce threads by means of the mouth, 

 so that it is not surprising that De Geer, Goureau, 

 and Riley were misled ; but the material is ob- 

 tained, as we have seen, from the anal organ, 

 which at ordinary times serves to excrete the 

 mucus which clothes the animal ; and Perris has 

 thus established in these creatures a form of spin- 

 ning certainly unlooked for and almost unique. 

 {To he concluded.') 



CLASSIFICATION OF BRITISH TICKS. 



By Edward G. Whelee. 



(Concluded from page 41.) 



Ixodes putus Cambridge. 



Synonyms : Hyalomma puta Cambridge, 1879 ; 

 Ixodes borealis Kramer and Neuman, 1883. 



Male. Unknown. 



Female. Length up to 10 mm. Body oval, 

 much rounded at the two ends, whether or not dis- 

 tended. Yellowish-brown, reddish, or blackish. 

 Tegument much striated, with short, white, regu- 

 larly scattered hairs both above and below. Shield 

 yellowish-brown, often darker at the sides ; sub- 

 triangular, and twice as wide in front as behind ; 

 rounded behind, hardly hollowed out in front. 

 Cervical grooves converging in front, then diverging 

 and a little concave within, enclosing a raised j3or- 

 tion. No lateral grooves ; punctuations fine and 

 numerous, with sometimes very short hairs. Sexual 

 orifice opposite the second pair of legs. Sexual 

 grooves widely separated behind. Anal grooves ob- 

 scure, reunited in front of anus. Peritremes round. 

 Legs very variable in size. False articulation near 

 the middle of the tarsi of the three hinder pairs. 



Nymph. (Fig. 17a, from specimen taken from 

 guillemot, Torbay.) Length, 1-59 mm. to 3'50 mm. 

 when fully distended. Colour (in spirits), brownish- 

 yellow. Body nearly round. Two long dorsal 



grooves, and one short central one behind. Hypo- 

 stome with two rows of teeth on each side. Palpi 

 furnished with long hairs. Haunches of legs 

 triangular, the third larger, and the fourth thicker 



Fig. 17a. Ixodes putus. Nymph. 



than the first and second. Anus almost in line 

 with the peritremes. When fully distended nearly 

 black, and legs dark testaceous. 



I have very lately received three specimens of 

 nymphs from Mr. S. F. Harmer, F.R.S., University 

 Museum of Zoology, Cambridge. The species has 

 not hitherto been reported in England. Neumann 

 says it has been found as far apart as Alaska and 

 Cape Horn, showing that it lives on migratory birds. 



