Uec.,i903.j Weeks: Evolution of Secoxdaries of Catocai.a. 225 



moths closely allied to the Catocala is Syneda. Insects of this genus 

 have pale yellow, transversely marked secondaries. Their habitat and 

 methods of concealment also furnish suggestions as to the origin of 

 this method of maculation by stripes as a protective character by 

 coincidence with environment. These moths occur in sandy locali- 

 ties where there is practically, to the ordinary view, but little oppor- 

 tunity for concealment, the surface of the ground being principally 

 bare and interspersed with patches of stunted and sparse vegetation 

 not more than a few inches in height, and strewn around which in 

 different directions lie masses or little heaps of dead grass, or other 

 fragments of withered plants. The moth generally rests upon the 

 ground in close proximity to small sticks, stones or where the 

 darkened sand and earth correspond more nearly with the general 

 coloration of the fore wings. Its most common attitude at the 

 moment of alighting is with wings expanded so as to match their strip- 

 ings and maculation with the mottled and banded appearance presented 

 by small differently colored stones and grass. Shortly afterward the 

 fore wings slowly close over the hind wings which still better match 

 the surroundings and render the moth invisible to the ordinary eye. 

 The stripings on all animals are a characteristic, generally admitted 

 to be useful in concealment from observation, as the vertical stripes 

 on the zebra, tiger, etc., which correspond with the alternate lights 

 and shadows of closely standing tree trunks or small stems of canes 

 and other tropical vegetation. In the same way many of the moths 

 which frequent grassy fields as the arctians, for instance, have wings 

 striped longitudinally with the evident intent of matching the light 

 and dark hues caused by the appearance of the light spaces between 

 the plant stalks. We may fairly infer therefore that the ancestor 

 of the Catocala was an insect which originally acquired its protec- 

 tive stripings merely for the purpose of concealment by harmonizing 

 and blending with its environment, and that aggressive coloration was 

 a subsequent acquisition which was improved and encouraged in the 

 same proportion as its value as a protective factor increased. 



We have still another form in various other families where the 

 secondary is provided with a large and prominent ocellus or eye- 

 shaped figure. Whether this be for the purpose of counterfeiting the 

 eyes of some predatory bird or animal and thus causing fear or whether 

 these pronounced eye -like spots are useful in diverting the attention 

 of an enemy, might afford a question for discussion, but according to 



