406 ARTICULATES I INSECTS. 



The Genus Gortyna contains the Spindle-worm Moth 

 and its allies, which in the larva state live in the roots 

 and stems of plants. 



The Spindle-worm Moth, or Corn Gortyna, G. zees, 

 Harr., expands about an inch and a half, and the fore 

 wings are rust-red mottled with gray, with a tawny patch 

 near the tip, and a few black dots on the veins ; hind 

 wings yellowish-gray, with two indistinct dusky bands and 

 a dusky spot. The caterpillar, known as the Spindle- 

 Worm, attains one inch in length, is smooth, naked, yel- 

 lowish, the head and top of the first and last rings black, 

 and a darker row of shining black dots across each of the 

 others. It bores into the stems of Indian corn. 



PHAL^NID^:, Latr., OR GEOMETRIC FAMILY. This 

 Family comprises moths whose larvae seem to measure 

 the surfaces over which they pass. The necessity of this 

 Fig. 3 oo. sort of movement results from the fact 



that they have only ten legs ; six true ones 

 under the fore part of the body, and four 

 prop-legs at the hind extremity ; three in- 



Geometer, or Span- . . ,- , . . 



worm. termediate pairs of prop-legs being want- 



ing. Some, however, have twelve or fourteen legs, but 

 in such cases the additional prop-legs are too short to 

 assist much in creeping, so that these also creep like those 

 above described. Geometrids live upon trees, and in most 

 cases undergo their transformation upon or in the ground, 

 which they reach by letting themselves down by a silken 

 thread, which they spin from their mouth while descend- 

 ing. They are generally smooth, and when at rest, many 

 of them stand on the two hind pairs of legs, with the body 

 extended, and thus may be easily mistaken for a little 

 twig. Often, when disturbed, they let themselves down, 

 and, when no danger is apprehended, return to the tree 

 again by the same thread by which they descended. In 

 the perfect state these insects are mainly slender-bodied 



