The Emergence of Broods XIX and XIII in 2024

In 2024, two broods of cicadas will be emerging at the same time. Brood XIX (The Great Southern brood) and Brood XIII (The Northern Illinois Brood). The last time two Broods had emerged in the same year was 2015. Many news articles and social media outlets are saying that this rare double brood emergence hasn't happened in 221 years. When they say it's been 221 years, they really mean to say that these two specific broods haven't emerged in 221 years. This brings the year back to 1803, when the Louisiana purchase had occurred. In reality, two broods emerge in the same year every 6 or 7 years give or take.

 

Regardless, this cicada season is still without a doubt a special one. I've numbered the reasons below...

1. The Brood's sheer size and occupancy put together, makes them impossible to ignore for news outlets and people in general.

2. It's a taste of all periodical cicada species in the same year.

3. There's an area in Illonois in which the two broods may meet and overlap.

4. It's a great year and opportunity for entomologists, as well as cicada enthusiasts, to learn something new about these amazing insects. 

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The Species

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Brood XIII (and all 17 year broods) consists of the species Magicicada Septendecim, Magicicada Cassini, and Magicicada Septendecula. These species vary in their call, size, and though very subtly, appearance. 

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- Magicicada Septendecim is one of the larger species. Its abdomen has some definitive and noticable stripes of orange to it, it's call sounds like something out of another galaxy. If you whistle for a few seconds, and then fade out at a lower pitch for a second, that's the best way I can describe the sound.

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- Magicicada Septendecula, is in the middle in terms of size (although I've seen that they can actually be larger than Septendecim at times). They have orange stripes on their abdomen, but these stripes are not as noticeable as in Septendecim. Their call is more comparable to that of a short period of chirping, just much faster than a bird would chirp. 

- Magicciada Cassini is the smallest of the three species. Their abdomen is completely black. Their call can be compared to a broken shush, immediately followed by a quick shush whine. If that makes sense. 

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All three of these species will be found in Brood XIII's location from Wisconsin to Iowa, Illinois, and Michigan areas in May -June. Chicago is the main city most people will talk about them I feel.

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Brood XIX (and all 13 year broods), consists of the species Magicicada Tredecim, Magicicada Tredecassini, Magicicada Tredecula, and Magicicada Neotredecim. 

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I've yet to experience these speies, but apparently, all of the decims and deculas in this group have more orangy abdomens. And the size variation is similar to the size variation of the 17 year cicada variety.

 

What I do know from researching... is that the only difference from the calls of septendecim males to tredecim males, is that the pitch of the call as a whole is lower. Neotredecim apparently, has a similar pitch to septendecim, or in between septendecim and tredecim's call. If this makes sense. Tredecassini is not really comparable by call because it's almost exactly the same as cassini in the 17 year variety. 

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These species will be present in Brood XIX's territory in April - June. Their territory is mostly across the southeast (with the exception of Florida) but stretching up into Illinois and across to Texas even. 

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This is what I've studied about the species differences between what can really be considered two different classes of periodical cicadas. I want to experience the emergence this spring for myself to get a better judgment as a whole. Tag along with me as I update my blog throughout the spring!

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