OR LIFE-HISTOET OP CERTAIN ACARINA. 391 



General form an elongated diamond, with curved sides. 



CeplialotTioraco and aldomen. Eostrum very small and colour- 

 less, articulated with the cephalothorax ; sides almost parallel ; 

 two short rod-like or tubular projections from the anterior 

 border of the rostrum, and two similar, but rather larger, inserted 

 in a notch in the side of the rostrum, like palpi. No demarcation 

 between cephalothorax and abdomen ; hinder portion of noto- 

 gaster covered by a brown, chitinous, shield-shaped plate, not 

 quite coming to the edge of the abdomen; the soft parts out- 

 side the plate ragged in outline and bearing a few short, clear 

 spines. Notogaster bearing four rows of very large serrated 

 spines. No part of the creature covered by any carapace. 



Legs of 5 free joints ; there is also a large basal portion which 

 may be an epimeron, or may be equivalent to a fixed coxa. 

 First pair articulated to the anterior margin, gradually diminished 

 in thickness towards the distal extremity ; every joint bears one 

 or more whorls of large spines ; there are several on the tarsi ; 

 which are terminated by small single claws on long straight 

 peduncles, with a very large serrated seta above it and another 

 nearly opposite. Second and third legs articulated at the side of 

 the body, slightly below ; somewhat similar in shape to the first 

 pair, but tarsi more curved, and terminated by a didactyle claw, 

 with caruncle ; setse smaller than those of the first leg, but the 

 penultimate joint of the second leg bears a curious curved 

 chitinous projection on the outside and a strongly pectinated 

 seta on the inside. Fourth legs short, but very thick, curved 

 inward, ending bluntly ; no claw nor caruncle, but two long 

 setse not quite terminal, the upper one being the longer. There 

 is a large spike on the inside of the penultinate joint directed 

 downward and backward, and a curved chitinous projection on 

 the outside, as in the second leg. A few other setse on the legs. 



The ventral surface shows a median chitinous ridge, or sternum, 

 with four transverse ridges or apodeniata running to the epimera 

 of the legs, and forming the skeleton. These divide the body into 

 eight spaces, each of which bears two or more clear spikes. 



The penis is long and straight, and is seen in the median line 

 below the shield-shaped plate. 



Female (figs. 2, 3). 

 Average length about "26 millim. 

 Average breadth about "22 millim. 



