A. C. OUDEMANS. ACARI. 145 



coxae III near the edge a short hair. On the coxal plates III a longer hair. In a line with 

 thèse hairs, before the génital aperture a pair of shorter hairs. Aside of the génital aperture, 

 above the posterior suckers a minute hair. Inside of coxae IV a long hair. Before the anal 

 suckers a short pin-shaped hair. On the posterior margin 3 pairs of trailing hairs, of which 

 the immost as long as the width of the abdomen, then a shorter pair, then, outmost, a pair 

 longer than the abdomen, in some individuals even as long as the whole body. 



Mandibles. Upper jaw with a little incisor behind the end-incisor, and three triangular 

 canines (or one canine and two molars). Lower jaw with. large end-incisor, a blunt triangular 

 canine, a larger triangular molar and a rounded ditto. 



Maxillae (Fig. 100) forming together a large trapézoïdal under-lip, longer than wide, 

 widest posteriori}', with two blunt, distally slightly excavate malae, a médian lip, with médian 

 triangular top, and two-jointed palpi, of which the first joint is twice longer than the distal 

 one. and bears ventrally and dorsally a short thin hair. The last joint is ventrally provided 

 with an oval spot and a short, curve, blunt olfactoric or taste-hair. Behind the malae a pair 

 of long thin hairs. 



Legs (Figg. 94, 95 and 97) shorter than the width of the abdomen. Legs I the thickest, 

 legs III the narrowest. Legs I : genu dorsally and distally with tactile hair; tibia dorsally 

 and distally with long tactile hair; tarsus dorsally and proximally with olfactoric hair and 

 distally with short tactile hair. Legs II: genu dorsally and proximally with tactile hair, dist- 

 ally with short stiff hair; tibia dorsally and distally with long tactile hair; tarsus dorsally 

 and proximally with olfactoric hair, in the middle and distally with short tactile hair. Legs III: 

 genu dorsally and distally with short tactile hair; tibia dorsally and distally with long tactile 

 hair; tarsus dorsally and distally with short tactile hair. Legs IV: tibia dorsally and distally 

 with long tactile hair; tarsus dorsally (Fig. 102) with two minute suckers standing a little 

 before and beyond the middle. In fig. 10 1 I hâve delineated the distal end of tibia I and 

 the proximal end of tarsus I; the olfactoric hair shows to be drum-stick-shaped and a little curve. 



Female (Fig. 103 — 106). Lengtli 312 — 552, •/.. Colour, shape and texture like in the maie. 

 The shape of the abdomen is of course liable to some variation, caused by the bearing one 

 or more eggs, so that in some individuals the abdomen may be swollen considerably. 



Dorsal side (Fig. 103). Like that of the maie. Pseudostigmatic organ, however, very 

 unlike to that of the maie, being flat, curve, proximally widest, gently diminishing in width 

 towards the distal end which is very fine, having very few, e. g. only two branches on the 

 concave side and more, e. g. 5 on the convex side. 



Ventral side (Fig. 104) like that of the maie, except in the following particularities. 

 The génital aperture reaches a little more forward than in the maie, and misses the chitinous 

 posterior limit. The anal aperture is far more backward than in the maie and flanked by 

 4 pairs of small hairs. The problematic light refracting spots are présent. 



Mandibles, maxillae, legs like in the maie except of course tarsus IV which misses the 

 two suckers. 



Habitat: on the head of Goura sp. (13 spécimens). 



Remarks. The lengtli of Tyroglyphus dimidiatus may vary considerably both in the 

 maie and female, as well as in différent races, especially in the female which may be swollen 

 so that its abdomen becomes nearly ball-shaped. My greatest individuals measure 800 ,u. The 



Nova Guinf.a. V. Zoologie. 19 



