i4^0. Mitt parasitical on Slugs* 



resembles in the swiftness of its motions, and also in having a 

 movable fingerlike process attached to the last articulation of 

 the palpus. But it differs essentially from that genus in its 

 place of residence, Erythrae^us not being parasitical ; and in its 

 being furnished with a haustellum, as far as I can perceive, 

 instead of mandibles. The feet and palpi are also much 

 shorter. If it be really hitherto undistinguished, as a pecu- 

 liar genus, I would propose for it the following name and 

 characters : — 



Philo'dromus.* 

 Gen. Char. — Os haustello terrainali, brevi, porrecto. Pa/pi duo, rostrum 

 longitudine paullulum excedentes, filiformes, quadriarticulati ; articulo 

 ultimo appendice mobili ad basim instructo. Oculi indistincti. 



Corpus ovale, setigerum. Pedes octo, subaequales ; unguibus instruct!. 

 Sp. 1. P. JCiMA^cuM mihi. 



P. flavo-albicans, pedibus pallide testaceis. 



Insecte des Lima9ons, Reaum. Mem. de PAcad. des Scien. 1710. 

 p. 305. pi. 8. 



Long, vix 1 lin. 

 Body oval, convex above, with the sides very much bulging between the 

 second and third pair of feet, beneath which, in some specimens, it is slightly 

 coarctate. Colour yellowish white, with the feet pale testaceous red ; upper 

 surface beset with short scattered bristles ; with two longer pairs, of which 

 one arises from the anterior part of the body, and is directed forwards ; 

 the other from the posterior part, immediately above the anus, and is 

 directed behind. The feet appear to consist each of about five articulations, 

 and are nearly of equal length ; the first pair being somewhat longer than 

 the others. The last joint terminates in a pair of strongly hooked claws, 

 surrounded by a coronet of bristles. A pair of short bristles also arise at 

 the junctures of the other articulations. 



Such is the result of my own observations upon this para- 

 site. The description which Reaumur gives of his in- 

 sect agrees with mine in all essential particulars, as does 

 his figure also, although this last is but rudely executed. 

 There are, however, one or two differences in our respective 

 accounts of its economy, which deserve to be pointed out : — 

 First, he appears to have met with his specimens upon snails ; 

 and the species represented in his plate are evidently the He- 

 lix pomatia and the Cyclostoma elegans Drap. Neither does 

 he make any mention of having seen these insects upon slugs. 

 Secondly, he notices their singular habit of retiring occasion- 

 ally within the body of the animal ; but speaks of them as 

 taking up their residence in the intestines of the snail, enter- 

 ing per amnrii and only quitting their abode when forced from 

 their retreat by the evacuation of the faeces. It is just possible 

 that Reaumur's insect may have been of a different species 

 from mine, although evidently of the same genus ; and in that 

 case it would be well characterised by these diflferent, yet at 



* From philed, to love, and dromos, running. 



