INTERNAL ANATOMY. 89 



cuticle near the edge of the genital aperture are two 

 spines which are probably protective, and may possibly 

 serve as guides (see fig. 4, which is Herieia Robinf). 

 At the proximal end of the organ are a pair of short 

 apophyses which afford a place of attachment for the 

 erector muscles (fig. 6). In Herieia Robini the penis 

 is of a very similar form, but the bulb is less sharply 

 defined and the tube less curved (fig. 4). 



The penis of Tyroglyphus longior was found by Nalepa 

 to be S-shaped.* Berlese figures a similar form for 

 the organ of Tyrogh/phus infestans.^ The penis of 

 Aleurobius farinas is well figured by Robin, who how- 

 ever in the explanation of the plate calls the species 

 T. siro, and calls the end of the ductus ejaculatorius the 

 penis ; both being errors. J He does not describe it, but 

 Nalepa says that the penis of T. siro is composed of 

 a three-edged, only slightly curved gutter, and has the 

 form of the beaks of some birds. In spite of Robin's 

 mistake of species his figure must closely resemble the 

 penis of T. siro, for Nalepa, who probably had over- 

 looked Robin's pi. v, fig. 5, says that Robin's figure is 

 very exact. In Carpoglyphus anonymus Nalepa says 

 that the penis is clavate and has a comb-like ridge on 

 the dorsal side ; it is wide and open proximally, closed 

 and narrower distally.|| Berlese figures the penis of 

 Trichotarsus xylocopds as sickle-shaped,T]~ that of Histio- 

 stoma fimentarium as simply conical. That of Chorto- 

 glyphus arcuatus is large, slightly curved, triangular in 

 section, and diminishes regularly from the proximal to 

 the distal end.** 



The penial supporting sclerites of the Tyroglyphidae 



* ' Abtbeil. I,' p. 214, pi. 1, figs. 3, 4. 



f Berlese, 'A. M. S.,' Fasc. 14, No. 6. This species is however 

 now admitted to be identical with T. longior. 



" Memoire zoologique et anatomique sur divers especes d'Aca- 

 riens de la Famille des Sarcoptides," 1860, ' Mem. Soc. Ntit. Moscou,' pp. 

 1 110, pi. viii, fig. 4. PI. v, fig. 5, proves Robin's mistake in the species. 



' Abtheil. I/ p. 215, and ' Abtb. II, ' pi. Hi, fig. 5. 



|| ' Abtheil. II,' p. 134, pi. iii, fig. 4. 



f Berlese, 'A. M. S./ Fasc. XVIII, No. 1. 



** Ibid., Fasc. IX, No. 



