Notes on TyrogJypliidse. By A. D. Michael. 27 



before being mixed with other bulbs of value ; and that, if they 

 be infected, sulphur, carbohc acid, or some other insecticide should 

 be tried. 



In keeping the present species, I soon began to breed Hi/popi 

 from the nymphs. The Hypojms is very different from that of 

 T. corticis, not only from its greater size, but also from its shorter 

 and broader form, different sucker-plate, the entire absence of the 

 eye-like organs, and many other particulars. In this instance 

 again I found what seems to me strong confirmation of my view 

 as to the circumstances under which Syi^in are produced. The 

 Bliizoghjplms was swarming on the hyacinth bulbs ; both sexes 

 were thriving ; breeding was going on very much more fi-eely than 

 the owners of bulbs would approve of ; the creatures were all only 

 too healthy, and were not in any way dried up or subject to any 

 adverse circumstances ; and yet Eypojn kept on appearing in large 

 numbers, and, at the moment of writing this, they are swarming 

 in my cells, accompanied, both there and on the bulbs, by numer- 

 ous smaller Hijpopi, being those of some species of the genus 

 called Serrafor by Megnin (his original T. rostro-serrafics), 

 Philostoma by Kramer, and Histiostoma by Canestrini and 

 Berlese. 



As Claparede's admirable figures exist in a journal so easily 

 accessible as the Zeitschrift fiir Wiss. Zool., I have not thought it 

 right to re-draw it in this Society's pubHcations, but I have figured 

 the Hypopus, which I believe to be unrecorded. 



Tyrogltphus coeticalis. 



Dermaleiehus malus Riley, 5th Missouri Eeport, 1873, p. 87. 



But not Acarus malus Shimer, Trans. 111. Hort. Soc. 1868-9. 



Tyroglyphus malus Murray, Economic Entom., Aptera, p. 275. 



The most striking characteristics of this species are the fact 

 that in the adult state the length is nearly four times the breadth ; 

 the shortness of the legs ; and the posterior chitinous projection of 

 the male. 



Male. 



Average length about • 35 mm. 



„ breadth „ "09 „ 



„ length of legs * 07 „ 



* 



Colour of rostrum and legs, light-reddish, chitinous, brown ; of 

 the remainder of the body semi-transparent milky-white. 



Texture smooth. 



Cephalothorax. Eostrum almost like a separate head, being 

 movably articulated to the remainder of the cephalothorax, into 



