10 OUTLINES OF ENTOMOLOGY. 



inals are punctured and the juices or blood extracted. In others, like 

 the Butterflies and Moths, the combined parts form a long, flexible 

 tube, usually called a tongue, through which the nectar of flowers and 

 similar fluids may be drawn. In others still, the lower lip and the 

 maxill together form a sort of tongue for collecting sweets, while the 

 mandibles are not altered. Bees and Wasps have this kind of mouth. 



The organs of vision are situated upon the epicranium in front or 

 near the top of the head. 



They consist of a pair of prominent compound eyes (see Figs. 2 

 and 3, M), composed of a great number of six-sided lenses. In shape 

 these compound eyes are round, oblong or reniform (kidney-shaped). 

 In addition to these, many insects are provided with three small single 

 eyes, called ocelli (sing, ocellus}, situated upon or near the apex of the 

 head, in a triangle, as shown in Fig. 2, c. 



All these eyes are fixed in their sockets, but protrude so much 

 that some of the lenses face in each direction, and the insect has no 

 need to turn its eyes to obtain warning of approaching danger, or in 

 its search for food. It has been suggested that the compound eyes- 

 serve the ordinary purposes of vision, while the ocelli are used upon 

 objects that are near and minute ; but this is mere conjecture. Some of 

 the best observers and most careful investigators assert that with all the 

 provision that has apparently been made for sight in insects their vision 

 would seem to be very imperfect, especially for objects at a distance. 



Black and brown are the colors most commonly seen in the eyes of 

 insects, but many species have eyes that gleam with the tints and bril- 

 liancy of jewels, and add not a little to the beauty of the species. 



The most striking appendages of the head of an insect are the 

 Feelers or Antennae (sing, antenna ). These are many-jointed organs in 

 which the sense of touch is thought chiefly to reside. Many experiments 

 go to show that they are also the organs of smell. They are of a great 

 variety of forms, a few of which are represented in Fig. 4. The differ- 

 ent shapes are distinguished as knobbed, capitate, laminate, pectinate? 

 filiform, etc. They are usually attached a little below and between 

 the eyes, as shown in figures 2 and 3. 



A knowledge of the form and position of the antennae is very im- 

 portant in the classification of insects, especially in such orders as the 

 Coleoptera (beetles). 



All the functions of the antennas are probably not yet known ; but 

 it has been ascertained that besides serving the purposes already men- 

 tioned, they are also indispensable in guiding the flight of all winged 



