xxxiv LLOYD'S NATURAL HISTORY. 



clmed to think that it may have been first suggested by the 

 colour of the Brimstone Butterfly, even now a very conspicuous 

 and abundant insect during most of the year, at least in the 

 South of England, and doubtless, in former times, far more 

 abundant than at present. The German word, "Falter," evi- 

 dently alludes to the folding of the wings ; and " Schmetter- 

 ling," probably to the erratic flight of the insect. We have no 

 equivalents for these words in English ; but the German word 

 " Motte " is generally applied to a Clothes-Moth. 



The head is provided with the principal organs of sense, the 

 thorax with those of locomotion, and the abdomen with those 

 of respiration and nutrition. 



The head is usually of harder consistency than the rest of 

 :he body, and is often more or less clothed with hair or scales. 

 The most conspicuous organs are the eyes, ocelli, antennae, 

 palpi, and proboscis. The top of the head is called the vertex, 

 the back the occiput, the front the face, and the space round 

 the eyes the orbits. 



The large compound eyes are placed on each side of the 

 head, and are composed of a great number of facets, varying in 

 number in different species. As many as 17,32 5 have beencounted 

 in the eye of a Butterfly. They are sometimes studded with 

 hairs, and are sometimes naked, and this is of some importance 

 as a subsidiary character in the classification of genera. The 

 number of facets has not yet been sufficiently investigated in vari- 

 ous species to be used in classification, nor do we know how 

 far it is constant in the same species. Between the eyes are 

 placed the ocelli, or simple eyes, on the summit of the head. 

 These eyes consist of a single facet, and vary in number from 

 one to three in various insects. In Moths there are always two, 

 when they are present at all, but in Butterflies and many genera 

 of Moths they are entirely absent. Their presence or absence 

 forms a generic character of importance among the Moths. 



