8 



As yet no trace is to be found of the pattern, which appears 

 later on. The stigmata are visible as white spots. On each segment 

 there is a number of warts (in most cases ten) each of which 

 bears a simple bristle. When the small caterpillars have obtained 

 a length of 7 mm. they are olive-green and no longer form such 

 a great contrast with the green Euphorbia leaves as before; still 

 they do not possess any definite pattern. After five days the first 

 moulting takes place and with it a very complicated pattern sud- 

 denly appears (fig. 38—39)." 



Weismann also mentions a full-grown Smerinthus{?) species 

 in the museum in Berlin of which he says, „that it is sparsely 

 covered with bristles but does not show a trace of any pattern, and 

 agrees all the more with the youngest stage of most of the now 

 living Spinr/idae as it also has short bristles thinly spread over 

 the surface of the animal. This ^living fossil" had a length of 6 cM." 



For the rest the pattern of the hairs resembles that which I 

 found amongst others in Sphinx liguMri and Smerinthtis tiliae. 



Weismann's classical treatise has rightly met with much appre- 

 ciation but, unfortunately, has found too little imitation. 



For a more exact insight into the system of the Lepidoptera a 

 complete knowledge of caterpillars will without doubt prove to be 

 of great value. 



The accuracy of Weismann's investigations and the great keen- 

 ness with which he has deducted very comprehensive theories 

 from apparently unimportant facts, guarantee to his work a pro- 

 minent place in zoological literature. 



In his next study Weismann (1876 11,) discusses the so-called 

 „ parallel rows". He starts from the following argument (1. c. p. 141) : 



„If the development of the organic world depends upon a 

 phyletic vital power, there must have taken place and still be taking 

 place what I call „phyletic parallelism", i. e. the development of 

 the two stages of metamorphic species must have taken place in 

 exactly parallel direction; each transformation of the butterfly 

 would have been accompanied or followed by a transformation of 

 the caterpillar, and the systematic groups of the butterflies would 



