IV.] INSECTS AND UMBELLIFERJL. 105 



not symmetrical, the outer ones being considerably 

 larger than the others, and in many Umbellifers the 

 florets themselves, on the outer edge of the umbel, 

 are considerably larger than the inner ones. This 

 distinction is carried still further in the Corn- 

 posits, where also the florets are so closely packed 

 together that the whole flowerhead is commonly, 

 though of course incorrectly, spoken of as a flower. 



H. Mtiller has recorded 73 species of insects 

 as frequenting the Wild Chervil. In some cases 

 the number was even greater, as for instance in 

 Heracleum, on which he has observed no less 

 than 118. That the number depends on the con- 

 spicuousness of the umbel he illustrates by the 

 following series, arranged in the order of the con- 

 spicuousness of the flowers, — viz., i. Heracleum, 2. 

 .iEgopodium, 3. Anthriscus (Chserophyllum) sylvestris, 

 4. Daucus, 5. Carum, 6. Chaerophyllum temulum, 7. 

 Torilis. On these he found the following number of 

 species of insects : 



Heracleum 118 



.(Egopodium 104 



Anthriscus sylvestris 73 



Daucus 6 J 



Carum S S 

 Chaerophyllum temulum 23 



Torilis 9 



The position of the honey on a flat disk,, which 

 renders it accessible to most insects, has the opposite 

 result as regards the Lepidoptera, which therefore, as 

 might naturally be expected, are but rare visitors of 



