1866.] RITCHIE — ON SPECTRUM FEMORATUM. 67 



Having studied the habits of this insect for some time, I shall 

 mention a few facts from actual observation, illustrating the 

 peculiar adaptation for its comfort and place in the animal economy, 

 and having also dissected carefully, and examined its external and 

 internal anatomy with the microscope, I may be able to mention 

 some new facts hitherto unobserved. 



We shall first look at the habits of this little creature ; the only 

 time they are to be seen in numbers, is during the latter part of 

 August and the month of September, when the males are in search 

 of the females ; you find them in rows on the bark of trees, 

 their anterior legs stretched out horizontally in a level with the 

 body ; at other times they are rarely met with, as they are pecu- 

 liarly solitary in their habits ; they are not easily disturbed by 

 the approach of any one, as instinct teaches them that they are 

 not easily observed ; however, when touched, the anterior legs are 

 dropped, and they make good their escape in rather an active 

 manner ; their motion is ambulatory, or a kind of trot. They 

 are exclusively herbivorous, living on the leaves of trees. 



We shall now look at their external anatomy ; the body is long 

 and cylindrical, head and eyes small, legs long, very perfect 

 mouth, antennas long and setaceous, the feet are armed with two 

 claws, and have a pulvillus or cushion, colour varies in the sexes, 

 the length of any of the males which have come under my notice, 

 has been from 2J- to 2f inches exclusive of antennae, the antennae 

 measuring about 2 J inches ; the length of the female from 3 to 

 3J inches, antennae 2 inches ; the body of the male is more 

 slender, and the colour of the legs of a green shade. The number 

 of joints in the antennae of those I have examined, amount to 

 fifty-eight in the female, and seventy- two in the male, the joints 

 gradually shortening to the tips ; the eyes are small. One thing 

 I may observe here, that there are no ocelli or simple eyes on the 

 head of these insects, a fact about which there has been some 

 dispute. Latreille who has also examined them, bears me out in 

 this, although Kirby says that three very visible ones are distin- 

 guished in the winged species. 



The trophi or organs of the mouth are well developed, serving 

 both for cutting and grinding their food. The mandibles are 

 rounded and blunt, the maxillae or lower jaws are obtuse, the 

 labial palpi are four jointed, and the maxillary palpi three jointed. 

 Another fact which I noticed, is the presence of a spur at the 

 base of the femur, which evidently has been overlooked, as Kirby 



