THE INSECT WORLD. 



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parent legs, but seems to crawl directly upon its belly, as do all 

 the other caterpillars of this family, most of which have similar, 

 though less developed, spinous processes. Another peculiarity 

 which this species shares with others in the family is, that when 

 handled, it causes a burning pain as if nettles had been touched. 

 The hollow spines are terminated with easily detachable, very 

 short, stiff tips, and at their base is a gland which secretes an 

 urticating liquid. Handling the caterpillars roughly results in 

 breaking off the little tips, which enter the skin and at the same 

 time release a little drop of liquid, which, entering the wound, 

 causes the burning sensation. With some persons this becomes 

 a serious matter ; first inflammation, then swelling sets in, and in 

 extreme cases a numbness or partial paralysis of the entire limb 

 ensues. As a rule, however, the irritation is local, and no worse 

 than would result from handling a nettle. The prompt applica- 

 tion of ammonia, bicarbonate of soda, or even strong brine 

 will generally act as an antidote. This saddle-back caterpillar 

 lives on a great variety of plants, including pear and rose, on 

 which it is sometimes found in numbers. When full grown it 

 spins an oval, brown, parchment-like cocoon, and in this remains 

 unchanged until spring ; then it transforms to a pupa, and from 

 this issues a brown moth, expanding less than an inch, and 

 known as Empretia stimulea. A number of other caterpillars of 

 this family attack fruit-trees, but always in such small numbers 

 that they can hardly be considered injurious. 



The family Psychidts is peculiar in that the larvae are encased 

 in sac-like structures which they carry about with them, and 

 from which they derive the common term "bag-worms." The 

 best known of these, " the" bag- worm, is Thyridopteryx epheni- 

 ercBformis. This is often common in orchards, and also attacks 

 shade-trees, but is perhaps most injurious on arbor-vitae hedges, 

 which it sometimes kills. On deciduous trees the insects are 

 usually noticed during the winter, when there may be found 

 hanging to the twigs and branches cone-shaped bags of silk 

 varying from a little less than an inch to an inch and a quarter in 

 length, and studded with bits of sticks and leaves. If the 

 smaller of these bags are cut open at this time there will be found 

 an empty pupa shell, but in the larger there will be found a mass 

 of yellow, fluffy material embedded in which is a great mass of eggs. 



