264 W. WESCHE. 



joined together, the last or true terminal joint in an atrophied 

 condition (Figs. 3, 4). It would thus seem that, in the antenna 

 of Diloplnis at least, joints may be lost either by fusion of the 

 middle ones or the disappearance of distal ones. 



THE CHARACTER OF THE HAIRS AND BRISTLES ON THE LEGS 

 OF DlPTERA AND OTHER INSECTS. 



In the striking reconstruction of the primitive dipteron I have 

 quoted, Williston has suggested that the body was without 

 differentiated bristles. This character may well be extended 

 to the limbs also. In 1902 I published some figures of the legs 

 of diptera, 1 but these w r ere mainly concerned with the strangest 

 forms I could select; though the hairs and bristles were arranged 

 in striking forms they were mostly subsidiary and depended on 

 the altered shapes of the femora, tibiae and tarsi. Later, in 

 igoS, 2 I gave twelve figures of the microscopic appearance of 

 preparations of legs taken from twelve different flies, three to 

 illustrate a simple type, four the raptorial type, four the second- 

 ary sexual type, and one the parasitic type. The study of the 

 limbs has led me to place considerable reliance on the hair and 

 bristles as characters, and I find myself quite in agreement with 

 Williston's idea that the simpler pubescence is the older form. 

 My selection, a purely chance one, gave me as a result the legs 

 of a tabanid, a leptid, and a stratiomyid as simple types. Going- 

 further back in an endeavor to realize what the primitive char- 

 acters might be, I examined preparations of Myriopoda, Blatta, 

 Forficula and Panorpa. These showed very wide differences 

 in the bristles and hair with which they were more or less covered. 

 Of the Myriopoda five species were examined, two Indian (Kash- 

 mir) and three British. A large Scolopendra is without pubes- 

 cence, and with only two small bristles at the penultimate 

 joint of the tarsi and two at the base of the claw. A species of 

 Sculigera has an extraordinary number of tarsal joints (39) 

 covered with short hairs, some of them short and stiff, with 

 bristles at the larger joints, the parts that may represent the 



1 " Modifications of the Legs of Some Dipterous Insects." Journal Queckett Club. 



2 "On the Microscope as an Aid in the Study of Biology in Insects." Journ. 

 Royal Microscopic Society, August, 1908. 



