Rhynehart — Life-History and Bionomics of the Flax Flea-Beetle, 527 



commence feeding. At this stage they are exceedingly fragile creatures, 

 and highly susceptible to excessive moisture. The greatest difficulty was 

 experienced in rearing them through to the second instar, and consequently 

 few data regarding the first larval instar have yet been secured. Moreover, 

 the feeding habit in the roots renders observation difficult. Individuals 

 were seen to have moulted eight and nine days after hatching ; but it cannot 

 be said with certainty if this is the average length of the first stage. The 

 larva becomes elongate as it grows older, but changes little in colour. Before 

 the moult it is narrowly elongate, and the bristle plates are well seen in 

 cleared specimens, while the head, and also the posterior extremity, appear 

 as yellow chitinised areas. 



(/) Second Instar : Duration and Habits. — The actual moulting process 

 has not been observed ; but from the study of the larva just before the 

 moult, it is inferred that the old cuticle splits along the mid-dorsal line of 

 the thorax, the rupture occurring in the sutures of the dorsal plates of the 

 three thoracic segments, and continuing towards the anterior of the head by 

 way of the epicranial and frontal sutures. Moulting is known to occur in 

 the leaf-tunnelling larvae of Fliyllotreta nemonim inside the tunnel ; and 

 it is believed that in the case of L. parmdus moulting usually occiars while 

 the larva is still feeding in the tunnel of the root. The larva is now longer 

 and a little stouter, and is thus admirably adapted for the habit which it 

 possesses of burrowing into the younger roots and feeding on their soft 

 parenchymatous tissues. Entrance is secured by means of a round hole not 

 much larger than will admit the larva. From this hole the tunnel usually 

 extends downwards into the younger and softer parts of the root. The larvae 

 occasionally come out of the tunnels to enter the root again at some other 

 part. 



The length ^ of the second larval stage was not determined by actual 

 observation, but from the appearance of the bristle plates, and from measure- 

 ments of the head, it is thought the instar has a somewhat similar duration 

 to that of the first. 



Ig) Final Instar : Duration and Habits. — Feeding in the root continues for 

 a week or more after the second moult, and the habits continue the same. 

 When fully fed, the larva leaves the root and comes into the soil. There it 

 wanders about, and ultimately prepares a crude cocoon of soil in which it 

 becomes transformed by a process of shrinkage in length, accompanied by an 

 increase in thickness, to what American workers term the " prepupa." It is 

 simply the final instar modified into a particular form during the transition 

 from active feeding larval life to the quiescent pupal condition. 



The total larval life from the time of hatching until the " prepupa " is 



