86 OUTLINES OF ENTOMOLOGY. 



merits each liind wing — occasionally enter lighted rooms on summer 

 nights; but, as a rule, the moths of this family are not much attracted 

 by light. The most delicately beautiful of our native species is the 

 Luna moth (Actias luna, Linn.), which is of a pale green color with an 

 eye spot at the end of the discal cell in each wing, and the hind wings 

 extended at the outer edges into lobes or tails sometimes one and one- 

 half inches long. The full grown larvse of these species are immense 

 caterpillars, usually of a green color, sparsely hairy and studded with 

 wart-like tubercles of brilliant colors, or bear, near the head, from one 

 to six long, spiny horns that give them a most formidable aspect. 



The invaluable and interesting Chinese silk-worm (Bomhyx mori^ 

 Linn.) is a near relative' of the species named above. It is of a bluish 

 or creamy white, with a few more or less distinct brown markings. 

 The surface is smooth, except for a few ridges and wrinkles on the 

 thoracic joints and a small pointed horn on the top of the eleventh 

 joint. All these species are very voracious, and feed for from four to 

 six weeks. 



The native spinners are often quite destructive to various kinds of 

 fruit and shade trees, while the Chinese silk-worm thrives best on the 

 White mulberry, but may be grown successfully on the Osage orange, 

 and, in the Southern States, it is said to feed on Alfalfa. The silk 

 gland, lying along the under side of the body, is very large in all the 

 typical Bombycids, and secretes a quantity of viscid fluid, which upon 

 being drawn out through the spineret on the labium, forms tine threads 

 of the exquisite substance known as sill". Of this the larvte form thick 

 oval, or slender, oblong cocoons, weaving layer over layer until about 

 half the substance of the caterpillar is transformed into the covering 

 for the pupa. In the latter stage our native species hibernate, but the 

 imported species cuts its way out in about two weeks, appearing as 

 a rather small, white moth, whose weak wings are incapable of sup- 

 porting it in flight. The female lays a quantity of eggs, and by means 

 of these the species is carried over winter. 



Among the most interesting species of Bombycids are the singular 

 forms termed "slug caterpillars." 



In these the feet are but slightly developed, and the insect moves 

 with a snail-like glide, over a leaf or other surface, by means of ridges 

 on the under side, leaving a slimy track behind it. Some have a 

 rectangular shape with several fleshy prominences on the back, others 

 are almost circular, or of the shape of a beech nut. Some are adorned 

 on top with a double row of plumy spines. 



Nearly all are brightly colored, or have the colors displayed in 

 peculiar and beautiful patterns. Great care must be exercised in 



