382 



ARBORICULTURL 



The Catalpa Sphinx. 



(Ceratomia catalpae Bois.) 



(By Lawrence Bruner, Lincoln, Neb.) 



Owing to the growing popularity of 

 the catalpa as shade, forest and orna- 

 mental trees, a brief account of their 

 most important insect enemy in the 

 United States will not be amiss at this 

 time. 



In the year 1836, or thereabouts, the 

 French Lepidopterist, J. A. Boisdual, 

 described a sphinx moth from Georgia, 

 under the technical name of Sphinx 

 catalpae. Judging from this name, its 

 host plant w^as know^n even then. Be 

 this as it may, the insect w^as scarcely 

 know^n to American Entomologists un- 

 til some years later, as will be gathered 

 from the fact that it was not included 

 in two of the most important lists of 

 North American Lepidopters published 

 in this country prior to 1 88 1 . 



With the introduction of catalpas in- 

 to towns, cities and parks for shade and 

 ornamental purposes, occasional re- 

 ports of the defoliation of such trees by 

 a large, rather brightly colored cater- 

 pillar drifted into the offices of state 

 and government entomologists and 

 other persons who w^ere know^n to be 

 more or less familiar with insects. The 

 life history and habits of the species 

 have been studied and several rather 

 complete accounts of the insect pub- 

 lished during the past twenty-six years. 



The accompanying illustration will 

 give the reader a very good idea of the 

 appearance of the catalpa sphinx in its 

 various stages of growth. At a is 

 is show^n the egg mass; at b the young 

 caterpillars immediately or soon after 

 hatching; at c the same after another 

 molt; at e, / and h the mature larva, 

 while 1. represents the chrysalis or pupa 



and k. the parent moth or imago. The 

 freshly hatched larva, of v/hich there 

 may be from 500 to a thousand in a 

 single community, is pale greenish 

 yellow with black caudal horn and 

 ocelli. As the insect becomes older 

 and increases in size, its head becomes 

 darker and the body is marked with 

 velvety black as shown in the illustra- 

 tion, though there is a great variation 

 in this respect, as will be seen by com- 

 paring g and i w^hich show the dorsal 

 portion of single segments from light 

 and dark colored caterpillars. The 

 eggs are laid in clusters on the under 

 side of the leaf. 



At first the larvae feed in companies, 

 but later, spread indiscriminately over 

 the tree. When mature, or fully fed, 

 they crawl to the ground and enter it 

 to a depth of about four inches. Here 

 they transf -rm to the pupa or chrysalis 

 stage w^hich is well represented at j. 

 This latter is about one and two-fifths 

 inches long, of a shiny reddish-brov/n 

 color and of the form indicated by the 

 illustration. The moth is grayish 

 brow^n or ashy in general tint, with the 

 shading as show^n in the picture. This 

 coloring gives it admirable protection 

 when resting upon the trunk or larger 

 branches of the tree. 



In the northern portion of this in- 

 sect's range, it is double brooded, the 

 first brood of caterpillars appearing dur- 

 ing June and July, w^hile the second one 

 is in evidence chiefly in the month of 

 August. A little further south, the 

 spring brood appears somew^hat earlier, 

 and a third generation of caterpillars 

 hatches late in August or early in Sept- 



