1 6 Guide to Insects and Ticks 



and are somewhat brush-like, but in the female they are very 

 short and simple. 



In Ano'plides the maxillary palps are long in both sexes. In 

 the male the apical joint is thickened and hairy, and diverges from 

 the proboscis, while in the female the palps are straight and lie 

 close to the sides of the proboscis for their whole length. 



The first three drawings exhibited show the head, as seen from 

 above, of the female Anoplieles macuUpennis, and the female and 

 male Cidex pi-incns. In order that the six piercing instruments 

 may be clearly seen, they are represented as dislodged from the 

 gutter-like labium, within which they are concealed in the living 

 insect. The next two drawings show the forms of the extremities 

 of the labrum, hypopharynx, maxillae and mandibles of female 

 specimens of Anopheles macitlipennis and Culex pipiens. The 

 labrum is viewed from beneath, the other parts from above. The 

 sixth drawing is that of a cross-section through the proboscis of a 

 female Culex pipiens, showing the relative positions of the piercing 

 organs when at rest ; and the last is a diagram of the terminal 

 portion of the labium of the same insect showing the form of the 

 labella as viewed from above and from below. 



On the sloping panel above the drawings are two diagrammatic 

 models of the head of a female culicine mosquito or gnat, viewed 

 from the side. The upper model shows the proboscis as it appears 

 when beginning to pierce, the lower one shows the disposition of 

 the parts when the lancets have penetrated a short distance into 

 the skin. The labium does not enter the skin, but loops down- 

 ward and backward beneath the body of the gnat, so that the six 

 lancets are no longer enclosed in its gutter-like groove ; the 

 apposed labella continue to surround the lancets, and slide along 

 them from point to base as the skin is penetrated. 



For comparison with the culicine and anopheliue mosquitoes 

 there is shown, at the East end of the case, a model, enlarged 

 28 diametei'S like those of the mosquitoes, of a common midge, 

 Chironomus plumosus Linn., a harmless insect, not to be mistaken 

 for a mosquito or gnat. The model represents the female midge ; 

 the differences between the heads of the two sexes are illustrated 

 in the two drawings above the model. An actual specimen of a 

 male midge is also exhibited. Cliiroitomtis plumosus is one of 

 the largest of the midges, and occurs in swarms in the air from 

 April to August. The larger midges may be distinguished from 



