220 A YEAR OF COSTA RICAN NATURAL HISTORY 



these hairs pointed forward as well as upward. The remain- 

 ing white hairs were inclined upward, backward and toward 

 the middle line of the body so as to give a " ridge-pole " effect 

 along the back. As the creature walked these hairs sep- 

 arated into cross-rows, corresponding to the segments, and 

 also opened down the middle line, exposing to view shorter, 

 brown hairs lying within the white ones, by which they were 

 concealed when the insect was at rest. In addition each 

 abdominal segment had on each side a bunch of white hairs 

 above and brown below; these bunches curved down to the 

 surface on which the caterpillar walked, simulating legs. 

 The hairs of the upper surface of the body were one-half 

 to three-quarters inches long, of the side bunches shorter; 

 all looked and felt soft and silky, nevertheless an incautious 

 prodding produced a severe stinging in the finger, the pain 

 lasting several hours. Next morning, after a long and tire- 

 some siege, this caterpillar was persuaded to sit for its 

 photograph. 



Two days later two very curious caterpillars attracted 

 our attention. One, with legs so short as to be invisible 

 from the side, was pale green in color with thirty-four clus- 

 ters of short blue-black spines arranged in four lengthwise 

 rows; each cluster comprised two to twelve spines. Its body 

 was plump and rounded at both ends so as to have the gen- 

 eral appearance, or rather shape, of a pillow (family Me- 

 galopygidae). 



The other caterpillar was covered with hairs and flattened 

 scales — red above the bases of the legs and over the head; 

 above the red they were black for the whole length of the 

 body as well as on the entire upper surface of the thorax; 

 above the black a band of white scales extended along each 

 side for the length of the abdomen, at the front end of which 

 the white bands of the two sides united on the back. Fi- 

 nally the middle of the upper surface of the abdomen was 



